It is unfortunate that we are so bad at doing relationships. This was not God's plan in the beginning.

The thing that separates marriage from all other relationships is the level of intimacy. Without the deepest level of intimacy, marriage is just like any other relationship. What is the deepest level of intimacy? When you can have all 3 combined in one relationship: Emotional, Spiritual and Physical intimacy.

The emotional intimacy is the one that the feeds the other two. This is the area where most marriages are lost long before they get divorced. Prioritizing your friendship helps keep the emotional intimacy growing.

The friendship between you and your spouse is very important. Your friendship is what holds the "like" between you. It is what makes you be kind when you are mad at each other. It is what helps apologies and forgiveness to happen sooner rather than later.

I could talk more about what friendship means in marriage. But my main goal here is to tell you to make your friendship a priority. How?

Stay curious about one another. Too often after a certain amount of time, people pridefully assume that they know their partner so well that they no longer have to learn about them. HUGE mistake. Stay curious about your partner. What makes them smile, and what makes them frown. What are their desires? Dreams? Problems? Fears? Likes?
Consistently spending quality time together. We can't get closer if we don't spend quality time together. "Quality Time" means time spent together focused on each other.
Laugh together as much as possible. God in his wisdom made something that feels good doing also healing for the soul. Laughter is medicine for a lot of things in life. And there's nothing more connecting than laughing with your life partner.

Focus on these 3 to start. This is how you prioritize your friendship. The reason you want to do this is because your friendship will carry you when the marriage seems too weak to continue.