I don’t know what to do

So i just got out of a 6 month relationship. It was a really rocky relationship. Arguing mostly because he would never call or text me or try to come see me. Our relationship was clearly going down hill. Once i sent this one guy nudes while dating my bf after a really bad fight. we were basically broken up and i felt guilty and told him. He flipped out but still stayed with me. Then i was on his phone and seen other girl nudes on his message with his friend. That his friend sent him but he never deleted the photos. I forgave him. This was at 3 months of dating. At 4 months i started to gain feelings for someone else and then tried to break up with my bf. We ended up getting back together. I still hung out and talked to the other guy. And my bf and i were great honestly. Then last night...He told me he stopped loving me weeks ago. About a month of our relationship was a lie. The whole time he was lying and pretending. And i know that he wasn’t going to ever break up with me. So i had to do it. For myself. And when he told me that i cried so hard and i couldn’t breathe. I had the worst panic attack. It was terrible. I don’t understand why he stopped. Like what did i do wrong? Why doesn’t he care or love me? I just wish i knew why. And it’s killing me inside and i don’t know how to get past it, because i know i’ll never get an answer.😔