What to do about a cheater?

Absolutely get rid of him. He is bad news..not just that, hes terrible news. You deserve a guy that cares for you, and only you. A guy who will treat you with respect, and any guy who has cheated on/for you..is not respectful. Leave him be...and let him figure out on his own, what a huge mistake he has made. It may be tough, but trust me, ive been there, and your much better off without him hun. Good luck!