In our society, we have a paradox. Most people want to get married and there is considerable research evidence that marriage has a wide range of benefits. But too often, the joy that accompanies the wedding celebration turns sour, and nearly half of couples who stand at the altar in hopeful excitement find themselves starting over after the trauma of divorce.

I was particularly interested in long-married elders’ advice about finding a life partner and staying married. In my new book, 30 Lessons for Loving (coming out this January), I surveyed 700 older Americans for their advice.

Here are three major (and somewhat surprising) lessons from the elders for finding a life partner and staying together “as long as you both shall live.”

Marry Someone a Lot Like You

I asked hundreds of elders what is most important for a long and happy marriage and their advice was just about unanimous: Opposites may attract, but they don’t make for great and lasting marriages. Based on their long experiences both in and out of love relationships, their first lesson is this: You are much more likely to have a satisfying marriage for a lifetime when you and your mate are fundamentally similar. And the most important thing to look for is similarity in your core values.

Take Emma Sylvester, who at 87 has been married for 58 years. As she put it with a smile, “It’s quite an achievement.”

I didn’t know it when I got married, but in retrospect I know it’s important to have the same basic values. In other words, if you’re a free spender, marry somebody who understands that. If you’re frugal, you need to marry somebody who understands that, because money is one of the stumbling blocks in marriages. And fortunately we had the same values on most things. Because of this, we really didn’t argue. And we really didn’t agonize over things. We came to our decisions by just realizing that we had usually the same goals. We both believed in education. We wanted to be moral according to society’s standards, to raise our children to be good citizens, and to be responsible in terms of finances.

Arguments emerge over apparently trivial issues, the elders told us, because they really reflect underlying values. Whether the wife purchases an expensive golf club or the husband a new electronic toy is not the core issue in what can become a monumental fight, but rather the deeper attitude toward what money means and whether the financial interests of the couple are more important than indulging an individual whim.

The elders urge people committing to a relationship to ask the question: Do we believe the same things in life are important? If problems develop in the relationship, these experts on long marriages say that value differences are likely to be at the heart of the problem.

Never Expect Your Partner to Change after Marriage

What about taking a leap of faith on the marriage under the assumption that you can change your partner after you’re married? The elders were as clear about this possibility as can be: Forget about it. According to them, entering into a marriage with the goal of changing one’s partner is a fool’s errand.

Rosie Eberle, 80 and happily married for 56 years, had a blunt comment to make about the entering into a marriage expecting to change one’s partner: “It’s just plain stupid.” She went on:

For heaven’s sake, don’t say “Oh, he’s this way now but he won’t always be like that.” Because they usually are, and you have to be careful, that’s all. So don’t marry someone and then think, “Oh, well he’ll change.” Or “I’m going to change him.” Believe me, it doesn’t happen. But people get real stubborn, and believe that can change a person later on, which never works.

Friendship Is as Important as Love

When asked the question: “What’s the secret to a long, happy marriage such as yours?” a common answer from people in long marriages was: “I married my best friend.” Similarly, from those whose marriages did not succeed, I often heard: “Well, we were good at love, but we never learned how to be friends.”

This response sounds peculiar, given that we are schooled in our culture to differentiate between friendship and romantic love. Indeed, television shows like “Will and Grace” and “Sex and the City” popularize the view that cross-sex friendship works best (or only) when one of the friends is gay. We see friends and spouse as two separate social categories that have different functions.

In contrast, the elders say that the special qualities of friendship are exactly what you want in your marriage. We typically look forward to being with friends, we relish their company, we relax with them, we share common interests and we talk openly. In contrast, we all encounter people who do not feel they can talk easily to their spouse (next time you are out for a fancy dinner, observe the couples who manage only a few uncomfortable words over two hours). What the elders suggest is that you look for the qualities of a friend — the capacity to comfortably “hang out” — in the person you choose to marry. As one 87-year old told me: “Think back to the playground when you were a child. Your spouse should be that other kid you would most like to play with!”

According to the elders, all marriages have to undergo a transition from the initial thrill of romantic attraction and — many were honest about it — overwhelming sexual desire to the stages when other things must become as or more significant. After being swept off one’s feet by true love, the elders caution you to ask “What’s next?” Will you wake up next to the same person for five or six decades and still find a person you like as well as love?

Patty Banas, 80, made a go of a first marriage when young, divorced, and then “got it right” in her very happy second marriage. She had one recommendation:

Be sure that you’re really good friends. That is the most important thing. All this — all the romance and the bells and the whistles and stuff is all very nice but it doesn’t last. Be sure that you’re really, very good friends.

As a relationship is moving into a serious phase, a question couples can and should discuss is: If we weren’t in love, would be friends? And when we move to something other than heart-thumping passion, what is there that will keep us together? (Hint: The answer should not be kids.) The answer is friendship, and if you don’t have it, don’t get married — it’s that simple.

Marriage will probably never go out of style in our culture. Why? There’s no more evocative summation than that from Ellie Banks, the mother of the most famous June bride of all in the 1950s film classic Father of the Bride:

“Oh, Stanley. I don’t know how to explain. A wedding. A church wedding. Well it’s, it’s what every girl dreams of. A bridal dress, the orange blossoms, the music. It’s something lovely to remember all the rest of her life.”

But after the bouquet is thrown and the last grain of rice is swept up, the realistic approach of those who have experienced decades of marriage can help us make our unions last.

I have to admit – I wasn’t sure that anything could be as much fun as writing the first book based on the Legacy Project – 30 Lessons for Living: Tried and True Advice from the Wisest Americans. There’s something special about “firsts” – and seeing my first book on our elders’ advice for living touch the lives of so many people has been incredibly rewarding.

But I learned that writing my second book was every bit as much fun as the first! I had heard from many readers that they loved the whole book, but there was one chapter that really grabbed them – the one on love and marriage. Some folks were buying the book just for that one chapter. Couples used it at rehearsal dinners and receptions, asking their guests to offer their lessons for the newlyweds.

I am glad I listened to them, because it led me on another journey – this time to find out what the oldest and wisest Americans advise the rest of us on how to have fulfilling and lifelong committed relationships. They  told me the good and the bad, offering 30 lessons for loving – and that became the title of the book.

30 Lessons for Loving: Advice from the Wisest Americans on Love, Relationships, and Marriage is almost here! It will be published and available in bookstores nationwide on January 8, 2015, and can be pre-ordered now. In the book, over 700 elders (some married for 60 years and more) talk honestly about the joys and difficulties of getting and staying married. They provide detailed advice that you  can use right away on questions like:

• How do I know someone is right for me?
• How can I improve communication with my partner?
• How can we avoid and resolve conflicts?
• How can we deal with stress – from jobs, kids, in-laws, chores, money?
• How can we keep the spark alive – for a lifetime?

Please stay tuned, as over the next few months we”ll be highlighting findings and surprises from the marriage advice of the elders. We’ll be posting new videos – and as ever looking for your comments and feedback!

What makes or breaks a marriage? To uncover the answer to that question, I have been interviewing the individuals I believe are the true experts: older people who have been married for decades. In hundreds of discussions with America’s elders (described in my recent book), one answer is surprisingly clear.

In looking at your marriage, they suggest you ask one key question: Can you talk with your spouse? And further: Can you talk with him or her about anything or are there “hot-spots” that are off-limits for conversation as a couple? It may work out if one partner declares a minor topic as off-limits (new phone apps, shoe sales or any interactive video game, for example). But as a rule, the elders in long marriages believe your partner simply must be someone you can talk to. Indeed, the most frequent source of “buyer’s remorse” in our respondents’ marriages was finding that a spouse just couldn’t or wouldn’t communicate.

Where is communication most important? These “experts” on marriage agreed that one thing all couples need to do — if you want to remain married as long as they have — is to learn to communicate about conflicts. More specifically, we all need to learn how to fight. I learned from the elders that fights are inevitable; it’s how we handle them that matters.

Dora is 86 years old and has been married for 67 years. When asked about the kind of advice she has for younger people about marriage, Dora’s lesson was about fighting:

Well, the only thing I can really think of is this: Just because you have a fight, it’s not the end of things. After all, there are two people living together, coming from different families, different upbringings. And if you fight, you have to recognize: “Oh, well, so what? We had a fight.” Ten minutes later you forget about it. As you get older, it becomes five minutes. Today people are, “Oh I had a fight,” and they act like it was the end of the world. You just have to move on. There’s at least two a week in this house!

So we have to get used to fights. Maybe that word is too strong for some couples, but even those who don’t “fight” have disagreements. And it is in communication around differences of opinion that the secret to a long marriage lies. You’ve just heard someone in a great marriage that has lasted 67 years tell you cheerfully that she and her husband fight twice a week. It’s not the fighting — it’s how you deal with it.

The elders proposed some creative ways of talking through disagreements before they get to the knock-down, drag-out level. Here are four suggestions for how to communicate when things get tense in your relationship.

Tip 1: If you are having trouble discussing something, get out of the house.

Gary, 75, suggests that a change of scene can help you communicate about a disagreement.

When you’re in your own home, you’re in the same atmosphere where the problems are going on. So you should go somewhere where you can talk — maybe it would be in the park, a restaurant or somewhere else. We’ve done that when we needed to. I’m not sure why that works better, but it does.

Tip 2: Find a way to blow off steam, and then engage with your partner.

Antoinette, 81, found that writing helped defuse conflicts and increased her ability to discuss them.

When I became terribly upset, I would sit down and write long letters to my husband, put them aside, read them the next day — and then throw them away. I think the big thing is to vent these things out of yourself, and you can do that in many ways. I found that writing helped.

Tip 3: Watch out for teasing.

Benjamin, 72, and his wife eliminated one way of relating that they found dangerous — it’s a strategy that could be used by many couples:

After we got married, we went through sort of a teasing phase, and it was getting out of hand. So we made a pact that we wouldn’t tease the other person at all, and it really helped. It can degenerate into something nasty, teasing. So we just stopped it. I may have been the worst one, the bigger tease. I’m kind of a jokester, and maybe I thought it was funny. But it digs a little too deep. And then she would probably retaliate. It certainly changes the other person’s attitude after they get teased. Looking back, that was an important moment, a turning moment point for us — to stop teasing. And it really cleared the air. It was wonderful.

Tip 4: Let your partner have his or her say.

The elders found making an effort to listen, and to clearly show your partner that you are listening, to be a major way to defuse conflict. They say it’s one of the major challenges in marriage — shutting up long enough to hear your partner’s perspective.

Here’s 82-year-old Natalie’s tip:

Before getting married, I had been single for quite a while — 27 years. I was used to running my own life. I thought I knew all the answers. When my husband would talk, instead of listening to him I would be thinking what to say… to contradict or to reinforce what I was trying to say. That is not the best thing when you communicate. You’ve really got to listen and let them have their say. When they’re done, ask, “What would you want?” or “What do you think would be the right thing we should do?” When I was in my twenties, I had all the answers. Now that I’m in my eighties, I’m not so sure my answers are always right.

April, 72, suggests “letting go.” She offers a very useful tip for deciding who should let what go:

It’s important to let some things go. You need to figure out what matters and what really doesn’t matter. There was one thing that we came to early on that really stayed with us: If we were in some sort of struggle over something, we would stop and say, “Which one of us is this more important to?” And when we could figure that out, the other one found it so much easier to let go. But we needed to consciously stop and figure it out.

So whether you call it a spat, a tiff or a disagreement, our elders say we must learn to fight fair — and it’s never too late to do so.

(Do you have marriage advice of your own? Please tell us your marriage lessons at our new site!)