But I wonder, how much would he put up with me if he were a single guy. He's pretty 'cool' and I imagine would have lots of options. I wonder where I woud fit in in that scenario (if he were a single guy).
There are a lot of great, single guys out there. And if it's the right one he's going to make you 100% number one (you won't have to "share him" with another woman), and he'll love you for your strengths and weaknesses. Go into some therapy and find out why you don't feel good enough about yourself that you don't think you can do better. Don't waste any more time. You are (or can be) more valuable then that... and find a stable, healthy, relatively baggageless single guy who can love you 100%.
But personally, I think even no man is better then the mess of a married one who's dealing with the disaster of a dysfunctional marriage/family. At least it gives you the opportunity to come across a more promising and healthier relationship without wasting your time.
I also suspect that whole situation has only pulled you down and made you feel worse about yourself.
I hope this doesn't sound like an attack or bashing. You sound like someone who wants a better life. It's a new year... maybe time to start a new one, and new relationships.
There is no arriving, ever. It is all a continual becoming.