When I started dating my current boyfriend, I met an old fling and had something going on him with him as well. It died down very quickly and things with my boyfriend progressed. I never expected our relationship to get serious later on so I didn't think much of it then but now I feel guilty all the time, it's like the foundation of our relationship is based on a lie. I feel like a bad person and I'm anxious whenever the topic of cheating comes up. Should I tell him the truth?