This is a tough one... don't you think? It sounds easy when you first meet the person and you are in love, and you feel like you would do anything to be with the person. But, then the years go by and you might start to see some of the negative sides of the other person, that is, your spouse. Then you get kids, then you work a lot, then there are expectations from all sides, while you are stressed, you would need some time for yourself, and life is just becoming messy. Then you might even think that the grass is greener on the other side.
It is one thing that you need to be healthy, exercise, and do things that are fully in your own power. But, to love your wife as a husband, that isn't always easy. In fact, it is often easier to choose the negative path, to choose the path in which you behave like a victim and always blame the other. But, that isn't what you kids should see. Your task is to love the kids' mother, your task is to lay down your life for your family, including your wife.
I believe the greatest example is Jesus, who gave his life for all of us.
Do you have any plants in your home? If a plant starts to dry out and look ugly, do you look at the plant and start to blame it for what's going on? Or is it possible that you haven't actually watered it and nourished it the way you were supposed to? Instead of blaming the other, it is wise to look at yourself and see if you are doing your part, if you are actually taking care of the plant/wife the way you are supposed to.