I hear a lot of idealism here, and that's great. But I'll bet that most of you who are condemning people for giving up on relationships too easily or not working hard enough at them or whatever have never experienced a bad marriage. I think most people that get divorced do so because they feel that they have no other option if they want to live happy lives for whatever years remain to them.
Try to imagine being trapped in a failed marriage, one where the respect and love and shared interests and sexual attraction are all long gone. Imagine looking down the gun barrel of spending FOREVER with a person that you don't love anymore, or fervently wish you had never met. What if your spouse is abusive? Alcoholic or a drug abuser? What if they deny you sex, or are so bored with it that it is clearly a chore? What if they are a terrible parent to your children, or mentally ill, or simply just miserable being anywhere near you? Or vice versa?
One truth of life is that people and relationships change. This may be hard to relate to when you are young -- but you are not going to be the same person at 40 that you were at 20. When things work well, partners change and age together, both of them growing and accommodating to each another as the years pass. Their relationship does not stay the same -- it changes too. Passion may give way to comfort and companionship.... shared interests may be replaced by shared experience in childrearing.... years spent together may overcome differences in temperment.... and a couple may grow old together happily. But other times, relationships sour and stagnate. Both partners may wish things to be different -- and work to try to make it different -- but at some point one or both partners realize that the marriage has become something that is ruining their lives, not enhancing them. Is it sad when marriages reach this state, and people decide to divorce? Of course. But is it really better to stay married and stay unhappy just to prove something to society or to God?
Personally, I think that the world is a better place since many of our societies have accepted divorce as a fact of life, and ceased treating divorced women as outcasts. I will probably catch some grief for this, but I am fatalist and a pragmatist about marriage and divorce. Even if conceived in love, some marriages are not good and the partners are better off divorced. Life is too short; everyone deserves a shot a happiness, and sometimes divorce is the only way to get there.