Most Helpful Girl
Honestly, at the end of the day he would be with you if he really wanted to be. It sounds like he likes the idea of you being around as a fallback girl incase things get messy with his girlfriend, and he says what he needs to, to keep you in place. I wouldn't wait around and I definitely wouldn't convince him to be with you. If you have to convince someone to be with you, than you don't want them!! I would tell him you're not waiting around for things to fall through for him and go about your life. If he knows you aren't waiting there for him maybe he will take you more seriously.
I know it's hard to walk away from someone you so deeply care about but it will only cause pain for you if you chose to wait and things don't work out in your favor. Look after you. Good luck hun!!