Help

Hello i have been dating for two years now.I cheated on my boyfriend exactly an year ago from today because when we started out i wasnt serious about the relationship.Now i am deeply inlove with him he claimed he forgave me but whenever he meets the guy i cheated on him with he falls into memory phase and gets angry and keeps quiet whenever we spend time.We are currently planning a wedding but am afraid and i dont know what to do now to help him heal since am inlove with him and i have been faithful ever since.

is the man you cheated with close ? why does he see him?