Life is unpredictable, swinging from joy to sorrow and back again, over and over and over. Marriage is naturally going to reflect that swinging.

My husband and I recently celebrated our 30th wedding anniversary. Unfortunately, we didn’t celebrate it together, as he was in Africa at the time for a regular teaching trip.

Somehow, when his most recent trip was scheduled we both overlooked that the travel dates included our anniversary. When we realized the oversight, he offered to reschedule his trip—no easy feat, as doing so would have affected not only him but those who were already making plans to receive him. I appreciated the offer but told him to proceed as planned. What mattered was not a single day on the calendar but a succession of days, one after another, going back 30 years.

Here are 13 things I’ve learned in that time about being and staying married.

1. Compromise Isn’t Always a Good Thing

If you like red wine and your spouse likes white, don’t meet halfway and get blush. Neither of you will be happy. Instead, buy a bottle of red and a bottle of white. If that’s not feasible, buy a bottle that will make at least one of you happy. The other person can enjoy vicariously and have his choice next time.

2. During a Disagreement, Someone Has to Prevail

Decision-making is hard enough when you have to do it alone, and harder still when you have to share it. When neither compromise nor turn-taking is realistic, someone must bow to the other. It is helpful to have a plan for who that will be.

My husband and I tend to defer to one another on matters for which one of us has more knowledge or hands-on experience. But if no agreement can be reached, the final decision is his. On this we take our cue from God’s word. All institutions need a chain of command for the sake of good order. Marriage is no different. The buck has to stop somewhere, and to be honest, I am glad it’s not with me.

3. It’s Okay to Not Like All the Same Things or Do Everything Together

My husband loves the beach. I can take it or leave it. On more than one occasion I have done the latter while he enjoys beach time on his own. When I do tag along, he makes sure I have a chair, a cold drink, and an umbrella before he goes bounding into the surf. I don’t make him feel guilty for leaving me behind, and he doesn’t make me feel guilty for not wanting to get in the water.

4. You Just Have to Overlook Some Things

The less-than-stellar cooking, messy night stand, clothes on the closet floor, forgotten birthday, dumb purchase . . . what does any of it really matter in the end, when you’re both staring down your own mortality?

5. Always Protect Each Other’s Reputations

When your spouse messes up you will be tempted to run blabbing to your friends, parents, children, or heaven forbid, social media. Don’t. When you married you became one flesh. When you shame your spouse, you shame yourself. You’re in this thing together.

This is not to say that you can’t do a little crying on your best friend’s shoulder when things get tough. But make sure it’s a friend who is pulling for both of you and the success of your marriage, not someone who is ready with a long list of reasons why it would be best to throw in the towel.

6. Beware Finger-Pointing

When you want to point the finger, remember there are three pointing back at you. I have found this to be one of the best ways to put my spouse’s supposed offenses in perspective. When I find myself getting frustrated with one of his less endearing habits or getting my feelings hurt because he is not behaving as I would like, I try to remind myself of all the times he has forgiven, overlooked, and tolerated my own transgressions. Suddenly it’s easier to do the same for him.

7. Go to Church

Ideally, invite God into your marriage from day one by getting married in the church. But if you didn’t do that, it’s never too late to start. Various studies suggest that a marriage built on a foundation of faith is more likely to remain standing when that foundation gets shaken. Going to church and being regularly reminded together of your sin and God’s love and forgiveness for each of you makes it easier to reflect that love and forgiveness to one another.

8. Pray Together

If you think sex fosters intimacy (and it does), just try praying together. There is no better way to show your vulnerability to one another than by baring your souls together before God. It also invites God’s ongoing participation in your life as a couple rather than keeping him conveniently confined to an hour every Sunday.

9. Be Open to the Blessing of Children

Children take you out of yourself, put everything else in more proper perspective, and cement your relationship with your spouse by providing a visible manifestation of your love and commitment. In loving and sacrificing together for the sake of your children, you will be better able to sacrificially love each other.

10. Do a Hobby or Project Together

Get a pet, grow a garden, undertake a house project, take a painting or dance class, or do something else that requires ongoing partnership and cooperation. You don’t have to do everything together (see No. 3), but you should do more together than sleep in the same bed and wave at one another as you come and go. Working together on a shared goal will build your sense of being a team and help you discover new things to appreciate (or overlook) about each other.

11. Don’t Try to Change Each Other

You liked each other enough 5, 10, 15, or 30 years ago to make a lifetime commitment. Don’t expect that the things you overlooked when you were in the early stages of infatuation are going to fade over time. If anything, they will become more pronounced. You bought the house. Expect that as it ages it’s going to get leaks, creaks, cracks, and drips. The answer is not to burn it down but to give it even more attention and TLC.

12. Be Each Other’s Advocate

Don’t “tease” or put each other down in public, not even in a joking way, but always speak well of one another. If you don’t, who will? Certainly not the world. Don’t be the world’s voice, constantly pointing out fault, but look at yourself as coach, cheerleader, and diehard fan all rolled into one. Cheer for each other’s accomplishments and share in each other’s sorrows. Ultimately you’re all each other has.

13. Forgive, Forgive, Forgive

Forgive. Forgive again. Don’t keep a record of wrongs. Speaking of No.13, go read 1 Corinthians 13. Then forgive some more.

There is no shortage of marriage articles out there. Some talk about how hard marriage is and how much work it requires. Others say if it’s hard you’re doing it wrong—it ought to be a blast! In my experience, it’s both.

When you marry someone, you choose to share your life with him or her. Life is unpredictable, swinging from joy to sorrow and back again, over and over and over. Marriage is naturally going to reflect the swinging of that pendulum. Don’t confuse your spouse with the pendulum, thinking that somehow if you jump off and find a different pendulum the swinging will stop. (It won’t.) Instead, hang on together with all your might and try to enjoy the ride.