What would you do????? help me please?

if he will cheat on her with you what makes you different that he wont do the same to you, don't mess with a guy that you know will cheat on his girl. he is no good you need to either wait till he breaks up with his girlfriend before even hanging out as friends b/c knowing that hes interested in you and that you to are interested in him also, it will definitely lead to something else. or you can just move on and find someone that isn't planning on cheating on there girlfriend...