My boyfriend keeps lying to me...?

I think you should do the same thing like your boyfriend is doing for now. Just acting. If he finds out about it, and he comes and mad at you, you can let him know that he's doing the wrong thing too. He will realize that his attitude is disliked by you. He may be wanted to change and be the one for you and keep loving you only. It may take times. But maybe you can also just be honest with him and break up if it's the best way.