What does it take to have a happy marriage that stays happy over several decades? It turns out there are some clear answers to that question.

Mark Manson is a blogger and entrepreneur who's best known as the author of bestseller The Subtle Art of Not Giving a Fuck. He's also a newlywed, having gotten married early this year. Like many newly married people, he began wondering what it takes to keep a marriage strong, and since he has a wide audience, he decided to ask them. He put out a call on his website for readers who had been married at least 10 years and were still happy in their marriages to tell him how they did it. Some 1,500 of them responded, sometimes at length.

Manson read through all the answers and found that many of the same patterns emerged over and over, and many of the answers covered the same themes. He found this very reassuring because it meant that there really is a formula to having a happy marriage.

My husband and I are about to celebrate our 17th wedding anniversary. That makes us rank amateurs compared to some of the really long-term couples who wrote to Manson. Still, we can confirm from our own marriage that the advice Manson received is absolutely right. You can find all of it here. Meantime, here's our take on some of Manson's readers' best tips:

1. There's a difference between love and romantic passion. Don't confuse the two.

Does your heart skip a beat when you see your loved one coming toward you? That's great, but that intensely romantic feeling is not going to stay the same over the years. In a good marriage, it gets replaced with something deeper and more solid, like a tree setting down long roots after a burst of flower. You'll know that you can count on your spouse to be there when you need him or her, to understand you better than anyone else, and to help you fulfill your biggest dreams.

In a way, that feeling of solidity and trust is the opposite of wild passion because wild passion always has uncertainty at its core. Not that you won't ever feel wild love for your partner--you will, sometimes. Other times, you will wish that same partner would go far, far away and never come back. And that's OK.

2. Respect trumps almost everything else.

Couples can disagree about a lot, but the real trouble starts when one stops respecting the other. At least, that's how it's been in every serious relationship I've had that ended.

Interestingly, Manson observed that couples who'd been together 10 to 15 years tended to stress the importance of communication, while those who'd been together 20 years or longer (sometimes much longer) emphasized respect instead. Manson guessed this was because long-term couples know that communication will break down at some point. I think it's because at some point, when you've been close for decades, you've pretty much said everything you have to say and communication becomes less of an issue.

Manson refers to respect as the bedrock of a relationship and I think that's exactly right. If you respect each other, and you share the same values, your relationship can survive almost anything. Without respect, it's almost impossible to make a long-term relationship work.

3. Learn how to fight.

I believe that if a couple is constantly fighting that's a bad sign--but if they never fight, that's a worse one. You're human, your spouse is human, and there will be times when you disagree. There will also be times when one of you feels wronged by the other.

So it's important that you fight, but it's also important how you fight. Even in the midst of a shouting match, when you are beside yourself with fury, will you refrain from saying things that can damage the relationship or your partner's self-esteem? As Manson notes, psychologist John Gottman is good at predicting whether a couple will divorce based on how they fight. So learn to fight fair, and in a way that does not inflict lasting wounds.

4. Make time for each other.

Life gets very full very quickly with jobs and kids and especially if you're starting a company. So you may have to be deliberate about making time to be with your spouse to do things together that are fun, as well as the things you need to do. Have a date night, plan the occasional weekend getaway, take vacations together. If you were dating instead of cohabiting, you would carefully plan your time together, and just because you're married doesn't mean you can skip this step. Your relationship needs these booster shots to stay healthy.

It also needs sex, something else you must make time for. A few years ago, my husband and I attended a tantric sex workshop that really opened my eyes on this point. Spontaneous sex may seem more natural or romantic but it often means squeezing in a quick session in between when you first open your eyes and when the alarm goes off, or rushing through an encounter before you go out for the evening.

You put planning and thought into most of the important stuff in your life, and sex deserves the same. With forethought, you can set the perfect scene for sex, and you can give each other all the time you need and deserve.

5. Make a choice.

Manson doesn't mention this specifically, and yet it's the subtext of almost every comment from his readers that he published. Getting into a relationship is a matter of choosing, and so is staying in one for the long term. If you're in a relationship that isn't working and doesn't fulfill you, or your spouse can't be the partner you need, then you may need to make a difficult choice about leaving. But if you're in the relationship and you want it to work, then you need to choose to be there.

That's a lesson I learned from my husband, and it took me a while because it goes against the mythology of love. Just as movies and songs tell you (falsely) that you should expect to feel romantic all the time and live happily ever after, they also tell you (falsely) that love is something that just happens to you. It's more like something you choose to create, especially after you've been married for a while.

A friend of my father's, and one of my mentors, told me that she married at 17 because she wanted to leave her father's house. She and her almost-as-young husband agreed they would give the marriage six months and then decide if they wanted to "renew." Six months later they did, so they decided to give it another six months. And so on and on until he died in his 90s.

That's marriage. You choose to commit to your spouse, and then you choose again and again. To accept them for who they are. To trust them to accept you. You choose to work through the tough stuff that inevitably will happen and to forgive the really hurtful things your spouse inevitably will do. You choose to talk about things that are hard to discuss because otherwise they'll pull you apart, and sometimes to shut up when you've talked about something enough.

A solid partnership can be the foundation on which everything else you do is built, so you must make it your top priority at least some of the time, and always when it needs to be. Marriage is something you choose, not every six months, but every single day. That choice can sustain you throughout the rest of your life.