There should always be an agreement on touchy things. You may have to compromise to get there, mind. If he ERP's for the sake of jerking off and avoiding sex with you, and you're not okay with that, he should pay attention to that and find a way to make it work for both of you. If he's ERPing because it's a part of an ongoing story where i happens without being forced and whatevernot and understands that there's a clear line between IC and OOC, then personally I wouldn't have a problem with it - But given that he has cheated on you irl before, I wouldn't be surprised if the latter wasn't the case. You seem to have made up your mind already, honestly it sounds like you'll be happier if you join the single club 
