It looks that way to you because you're a man. Many of the lifelong marriages of previous generations were a fantastic deal for the husband but hell on earth for the wife. Now that women have the educational and economic freedom to get good jobs and support themselves, the social freedom to be people and not just women, and the biological freedom to not be baby machines, they're demanding a different kind of life than their mothers had. Us guys ain't figured that out yet. Once we get with the program they'll come back and we'll have stronger marriages than before. In any case, most marriages in the USA last at least ten years. That's not eternity but it's certainly long enough to establish a relationship that becomes part of the lifelong identity of both partners.