Leaving my hs friendgroup

So I (21m) am in the process of leaving my highschool friend group bc I’ve realized lately that they’re all getting super mean and the “leader” of the group has never treated me well like they have with the others. I am a little bigger than them so i’ve always been treated like the fat funny friend by most of them, maybe it intentionally but imo it’s impact over intent.

They also were all incredibly disrespectful to my boyfriend (20m) and the leader was the main culprit and I just don’t want to force him into that anymore. I also go to a school farther away from where they all live and I feel like them staying all together has made it very cliquey and exclusive. My bsf (21) throughout high school i am also falling out with because she’s still involved in the friend group and peeved with my bf for defending himself. It’s hard but I feel like we haven’t jived like we use to so I think it was inevitable. I am happy though to finally move on and start making more friends that won’t disrespect me or my boyfriend and overall that I will just be able to be myself with. Multiple people have also left the friend-group over time and I think it’s because it’s so much different than it was in hs and we’re all growing at much different rates.

TL;DR

how do I not feel guilty about what’s best for me and my bf mentally? I keep trying to have someone to blame and getting angry but I need to realize that things like this happen. How do I make new friends?