I think Colleen stays for a mix of different reasons. I think having been together from such a young age, she'll lack her own identity and will largely feel like a codependent relationship (whether it is or isn't is a different matter), but that would be a scary prospect. She has mentioned her religion and that her belief has always been to try and keep the family together, even though it won't be setting the best example for her boys in terms of how to treat people. I also think that she might have weighed up the decision of what's worse... separating and being miserable or staying together and being miserable. One might have more benefits than the other. As much as I wish she'd make a stand against him and as behaviour, I do feel for her as I can't say that I'd be strong enough to leave either and it wouldn't be the money for me.