Ex boyfriend

My boyfriend of 2 years put up a lot from me for a while, we were going through this bad time always fighting and he wasn't paying attention to me, so i flirted with some "punk" guys and well that went a bit to far when one of them stared something with me, i left straight away and told me bf what happened. he wasn't to happy but said he could forgive me, about a month later i went to his work and i was waiting for him and i was talking to a guy that he worked with (which the guy didn't no i was going out with my bf) i saw my bf and went outside and the guy said to my bf that i told the guy that i wanted to meet up later on to night (which i didn't) but my bf didn't believe me and dumped me right there!! i was in tears for a month or so, then went back to that guy and talked to him for a while which i ended up crying and he hugged me when my ex bf came out and hit the other guy! I still love my ex bf but there is nothing we can do to make it better. But 5 months later me and his best mate started to see each other without telling him.