This is life unfortunately. At school more than half of my friends' parents were all split, and as I get older I come across SO MANY people (through work and social) that are on 3rd and 4th marriages. It sometimes puts me right off the prospect of marriage when they go on about the divorcing process. I dont' know what it was, but in my grandparents day couples seemed to stay together despite hating each other (as my gran once told me in regard to people she knew), but now people just seem more ready to admit they can't try anymore. While it's sad, it's much healthier to split, I think.
I've got friends who are in their second/approaching third years of marriage and they all still seem to be in their honeymoon periods. It's lovely to still see and I just hope more of them stay together long term than not, but it's very early days. Some of our friendship group have yet to marry (inc myself) and we mainly comprise of the ones that aren't sure whether we need or even want marriage. We pref holidays and not being tied to people generally. My now married friends are apprehensive about how future kids, money issues can all play a part in what was once happy turning sour, but no point worrying about what is yet to happen.