me and my girlfriend have been talking for about eight months been together for six there’s a guy that I think she has history with And there has been a series of red flags in my opinion but she denies anything ever happened between them despite telling me she slept with this guy when we were still friends just to try to see if she could get a reaction from me at least that’s what she tells me This was before we were even talking now she is taking a class with him should I be concerned