As some context me (19f) and my boyfriend Matt (19m) have been dating for almost a year. Recently my little brother (7m) got into a car crash because a drunk driver hit them and he didn't make it. A few months prior he had gotten surgery and they gave him a choice of blankets. He got one that had bumblebees on it since we would call him bumblebee. After he passed my mom couldn't really take it and she ended up going to therapy for grief (She was the one driving). My little brother was like my best friend and I would always take care of him and my other little siblings a lot. I ended up taking his blanket for something I'd have. Me and my boyfriend are close and he would always care. I told him what happened to my brother and that I took the blanket. He started comforting me and helping out. More recently we have been drifting apart. He has stopped coming to ask if I was ok, and he would always come home late. He would say it was work which I told myself he's right but I never believed it. The other day I come home a little later than usual because my boss wanted me to finish some work I missed on my days off. When I got home I saw Matt's car and didn't think anything of it. I went inside and he wasn't there. I looked around and didn't see the blanket where I left it. I saw Matt was outside using our fire pit and asked if he knew where it was. He pointed to the fire with the biggest smirk on his face. I saw the colors and bees in there and I completely broke down. I pulled myself together and yelled at him something along the lines of "I can't believe you would do this you know what this means to me". I then yelled at him to leave my house and not to come back and I would have his stuff outside. I then got many texts and missed calls from his family and friends saying I am the asshole and that I'm overreacting. My family agrees that what I did was right since they know what my brother meant to me. I then found out he was cheating on me with my best friend when she started to take his side on things. She would usually comfort me as well but drifted away around the same time he did. Am I the asshole?