Firstly well done in writing a novel, it's not an easy task as I am a writer of children's books, after years only now ready for representation! (anyway)
I think your story is one that will hit home with a lot of people, mostly women as this is probably your target audience. I think the days of a happy conventional ending are over. Personally I think she should end up on her own, having ruined two chances, but this is the lesson she is learning in life?
I just think that the message should be, less about 'being' with a man but more 'being happy' with yourself!
Good luck and keep us posted!