There are times when relationships change. Because people are mutable, relationships by default are too. Things change, but that doesn't mean you can't protect your marriage in the midst of those changes that occur.
As you move through life together with your mate, remember that your spouse is human. That person is changing, evolving as lessons are learned and situations happen. Give your mate room to grow and choose to grow with them. Don't get so comfortable in the relationship that you begin to take your spouse for granted, assuming everything will always be how it has always been. Rather, look for the opportunities to share growth together. Share in all times, good and bad. This is the makings of a good marriage!