I need advice !

Okay so before me and my boyfriend started going out I was talking to a guy for about 4 months, and we ended up meeting up one day and i was so happy the way he treated me was amazing. Anyways me and my boyfriend are going to be 9 months soon and I can’t stop thinking about the other guy. So I ended up finding him on instagram, and I think he has a girlfriend and I’m pretty jealous because that could’ve been me if I didn’t mess up what we had. So I really need help ladies. I don’t know what to do. I’m confused pls help