Love is a daily decision. That’s one of the key things I learned after talking to couples who improved their marriage through adversity. Each day we have choices to make about how we spend our time, what kind of effort we put in the marriage, and whether we offer a kind word or a complaint.

In my research, I wanted to talk to couples who didn’t just get through everyday life making good choices, but had unique challenges or tests. What is different about the couples who become stronger when faced with adversity compared with the couples that falter? How can some marriages survive repeated crises, while others that seem fortunate don’t stand the test of time? That’s what I set out to learn and share in my book, First Kiss to Lasting Bliss: Hope & Inspiration for Your Marriage.

I tell the stories of some couples whose lives didn’t go according to their plans. From losing a child, experiencing brain injury or overcoming drug addiction to learning how to develop trust after infidelity, or to reintegrate after a military separation, they had many difficult challenges. These couples didn’t just survive, they became great love stories of resilience and hope. I share their stories—mistakes and successes—because I think we doubt we could survive given the same obstacles. From them, we learn how success is possible.

Thankfully, most of us (we hope) will not experience the level of crises many of them did, but that doesn’t mean marriage or life will be easy, that there will be no valleys next to the hills. Even when things do go right eventually, they often don’t go right in our perfect timing. Here are a few lessons I learned from these couples:

Focus on your strengths, not your sorrows. When things aren’t going well in marriage, it’s so easy to focus on our faults and problems. But focusing on our spouse’s positive attributes, on what we are grateful for, and on what is good in the marriage can help us see our relationship in a better light. Most marriages have a few perpetual issues that never get resolved. If they are not deal-breakers, we need to give them less attention.

Forgiveness is a gift for the giver and the receiver. A marriage that harbors negativity and lack of forgiveness in the small, everyday things can be in bigger trouble than a marriage that has one big obstacle to overcome. We don’t just forgive because we want to be nice to our spouse. Withholding forgiveness can be emotionally and even physically harmful, say medical experts. It poisons the marriage, to boot. We may even be holding grudges for misunderstandings or trivial matters. Forgiveness is one of the essential keys to a happy marriage.

Live each day with gratitude, and infuse your marriage with it. A Blackhawk pilot led a unit in Iraq and performed MedEvac flights while under fire, while his wife waited at home with their four young children wondering if her husband will make it back. These are two people you wouldn’t expect to be living in gratitude. You’d expect their days to be filled with worry. However, a shift in their mindset changed the way they viewed their marriage and life in general. In fact, this young couple says a dangerous deployment was one of the best things that happened to their marriage because it taught them how to focus daily on gratitude for each other and thankfulness for all those around them.

Focusing on gratitude is especially helpful when things are not going well, although we are less likely to focus on thankfulness during tough times. This is exactly when we need it most.

Have each other’s back. Be a team. We don’t live out our marriages in a bubble, and unfortunately, outsiders may sometimes try to intrude on our happiness and create instability. This was the case for an interracial couple that had dated for many years and had a strong, loving marriage. However, his family was unsupportive of the marriage and tried to undermine it by habitually disrespecting his wife.

After years of feeling unsupported by her husband, who didn’t want to admit his family might be racist, the marriage nearly fractured. However, they were able to learn how to create boundaries and expectations for those outside their family unit. They became stronger and learned to "have one another’s back."

It’s not unusual to have family or friends who do things to undermine a family unit. A husband and wife need to make their relationship primary. A wife shouldn’t try to please her parents above her spouse, for example. By viewing ourselves as a team, we become more resilient.

Lori Lowe is a journalist, GenXer and marriage researcher. She has been married to her college sweetheart since 1995. They have two children together, one crazy cat, and two aquatic frogs. Lori is the author of "First Kiss to Lasting Bliss: Hope & Inspiration for Your Marriage," available on Amazon.com or from your favorite e-book retailer. For more visit Marriage Gems or connect with Lori at www.Facebook.com/LastingBliss or on Twitter @LoriLowe.