You don't have to stop loving him but it's probably better to break up with him anyway if you care about your own feelings. Stopping loving someone isn't usually something easy to force yourself through and I'm sure part of you will always love him but if you don't want to be used it's best to break up with him.
One: Once a cheater, always a cheater. You cannot make a tiger change its stripes. Two: Dump his ass. Apparently he doesn't love you, and if he did he isn't showing it by cheating on you. Three: These questions belong in the "Help with Life" forum.
My mom once got French onion soup at a restaurant, and when it came to her, she complained that it was cold. "Send it back," I said. But she wouldn't because she was hungry. So she kept complaining. Finally, I said, "Look. If you aren't going to do anything about it, you deserve to eat cold soup."
Advice: stop being a doormat, stop whining, take control of your life and move the fuck on.
You know what you have to do, you're just looking for someone to tell you how to avoid doing it. Well, sorry, life doesn't work that way. You have to live your own life. If you act like a doormat, then be prepared for people to walk on you.