Based on what you're saying ur relationship is all about sex, u thought it's was more than that but it's not. U gave him what he's looking for in the meantime he's getting it from other too which he thinks it's fresh or maybe develop some feelings for her. What I'm saying is if the man is all around u for sex and cheated on u you better get over with it. He only comes when he's alone. So forget what you were and try to figure out life u had before him or u think you'll live without him.