They may be the one and only person you are physically intimate with, but healthy relationships require at least 3 other types of intimacy to be healthy and successful.
Emotional intimacy goes beyond having regular conversations about your relationship to expressing how you feel and being supportive of one another in all areas of life. This includes hearing how your partner feels, both good and bad, about your relationship—to empathizing while they vent about work, family, friends, or a stressful day. It includes cheering them on when they are happy.
You need your partner to be someone you can have thoughtful conversations with. Yes, you may have areas of interest or expertise that vary greatly from your partner, but you need to be able to have deep and interesting conversations. You must also support them in their intellectual endeavors.
One of the primary reasons for relationship ruts is that your lives become monotonous. Schedules are busy with work and kids, but you must make time to try new things together. This could be as simple as going to a new restaurant, on a weekend getaway to somewhere neither of you has been before, or trying out a new activity together.
Spiritual intimacy may also be a priority for your relationship but it isn’t essential for all couples.