Adults can barely grasp the potential rending of a marriage.
Look at it from a child's (regardless of age) perspective.
Will I lose one of my parents? Where will I live? Do I have to choose/take care of/protect mom and/or dad? If their love went away, does that mean they'll stop loving me, too? This really really hurts. Is it my fault? I hate my mom/dad/parents. I love my mom/dad/parents. If I'm really good/really bad will they come back together? But I really want my family! Hey, maybe I can get that puppy now! What's for dinner? But I don't want to go to bed now.
Different ways of thinking.. one in dealing with your wife, the other with your children. The love of a parent, the confidence a child has in that love is a beautiful thing.