I don't have children, and appreciate that this will make my views differ from those that do. I left my husband last year, we'd been together 17 years (since we were both 18) and were married for 4 years.
Things had never been fairytale between us, but I thought that was just real life. We had our ups and downs, and I suffer from long term depression so was never sure what was caused by that as opposed to our relationship. I wanted children but he insisted he wasn't ready - I now see that as a delaying tactic and he would never have been ready. We just bumbled along year after year and nothing ever really happened. We had our individual hobbies but did very little together. I'd considered moving out before but there were always reasons that held me back - we had dogs, we had a nice house, we both had minor health problems etc and for a while these reasons convinced me that I'd be better off staying.
My wake up call came when both my grandmothers died within a couple of months of each other, both aged 90. It occurred to me that if I stuck as I was I had potentially another 55 years of this. It wouldn't be unbearable, but there was the potential for so much else to happen in my life. I went to counselling to sort out how I was feeling (I encouraged him to do the same but he wanted us to do relationship counselling and wouldn't go on his own) and I realised pretty quickly that in order for us to be happy one of us would have to change who we were. I knew that was unrealistic and unfair, so I decided that I'd had enough. The reasons that had previously made me feel unable to leave stopped being a big issue and all of a sudden I took on a 'we'll work it out' philosophy (thanks mainly to my counsellor who made me realise exactly what it was that I wanted).
It hasn't been the easiest time, and I half think that the divorce process in this country is intended to make everyone part on bad terms. It was hard coming up with examples of unreasonable behaviour as they all sounded so petty, but added together they weren't and were just many small examples of why we weren't happy anymore. We are divorced now but we share 'custody' of the dog so still have regular contact. He and I both have new partners and I am the happiest I have ever been.
From a child's point of view though, my parents never got on well and finally divorced when I was 19. My older sister and I would far rather they had called it quits when we were younger and avoided all the years of stress, tension and arguments. Having divorced parents who are happier has to be better than parents who claim they are staying together for the kids.