Fio and Anna I agree with you both.
I don't think the question is about being married or not. It's about commitment, and loyalty, and love, and making the other person happy. However each individual couple chooses to do that is up to them.
For me, marriage meant a lot. My dad was an adulterer and I was determined that if I ever got married I would learn from his mistakes, and always make sure I remember why I married H in the first place.
So after 14 years with H, he recently had an affair, but I forgave, took him back, wanted to work on whatever issues led to it happening. But sadly H does not have the same values. Like you say, I could 'give' everything I have (and I pretty much have done), but if he doesn't give the same in return it can't possiby work.
Strangely, H comes from a stable home and his parents have been together since teenagers and happily married for 30 years. Can't explain that one!
I think perhaps H's role models have made things look 'easy' in hiding any problems they've ever had... so the minute our relationship got hard he decided it somehow mustn't be 'right', and bailed out...
Interesting thread