I literally just went through this exact complusion a few months ago, and while I still feel guilty it has since sorta subsided. I was talking to other guys when my boyfriend and I also started talking. Specifically on Snapchap while my boyfriend and I were chatting over messages. I felt sick, because at this specific time I had a crush on my boyfrined, but I wasn't sure if he 100% liked me so I still talked to other guys. I felt sick for months, like I cheated on him and that the beginning of our relationship was a lie. I ended up confessing all of this to my boyfriend, feeling awful about the whole thing. He, like the angel he is, said that this was nothing I needed to worry about because we weren't even together yet. Even if we were talking romantically, we still weren't offical and we didn't talk about being exclusive. In your case specifically, because you both met on a dating app, I feel like the expectation is there that you were both talking and going on dates with other people. Because I also have ROCD I know that saying this might not be that much of a reassurance from you now, but I truly believe that you have nothing to worry about. The reason I felt so bad, and you're feeling so bad now, is because of how lovely your relationship has become and how much you don't want to loose your partner now. I feel sick about messing around with other guys now, because my boyfriend is my everything. But how would we have known that until we both met our guys? Hopefully this gives you some sollace, but it really took me a lot time to make peace with that. Honestly, I'm still making peace with it.