I’ve known my boyfriend for years. When we first met I also met his cousin. His cousin was aggressive in perusing me and we got drunk and had sex. We were friends with benefits for a while after that but no relationship. Fast forward to today, me and my boyfriend are getting serious. We work together so we spent a lot of time together and I fell for him. He and his cousin don’t really talk. He doesn’t come from a close family. I know since they don’t talk it shouldn’t matter but at the end of the day it’s still his cousin. I feel like I should tell him because if it comes up later it’ll be so much worse but if I tell him and we break up it’ll devastate me. If the roles were reversed I would want to know. Any andvice?