Not to be mean, but it sounds to me like you don't have to worry about telling him that you wouldn't see a guy who is still in contact with his ex because if he wanted to be with you....he would be. If you are referring to him as your crush and all that has happened is some talk of feelings, that is pretty insignificant. Actions speak louder than words. He is out with her and not with you. Again, I am not trying to be mean. Just going with the facts here. I would not get involved at this point in expressing your feeling any further or believing the song he is singing to you.