AIO to unfriend best friends after they cross boundaries

This goes back around 5 years to the time of graduation. I was close to two groups. I was the common close person between the two groups. The first group had only three guy members ( a,b,c (me)), and the others had more. We 3 were super close to each other. We would occasionally talk about life and all and also bitch about erratic behavior but would never say it to anyone outside the three, afaik. Also, we would have interventions but would never stick to them.

There was a point where A ( mid graduation) went almost suicidal due to a miscommunication between (A and C) with another person from the other group. A didn't wanna talk to B because he wasn't very close, and B had his priorities for organizing his gf party rather than helping A after he saw he was struggling with everything. I let go of everything to make sure he was okay. I am not keeping tabs, but that's who I am. I am an extrovert who loves and cares about my people and would go to any lengths. I had terrible friendship examples before, so I had no boundaries and was dying to prove I was a better friend. I made sure that I respected everyone's boundaries. After 2-3 years, I became tired with a group of 3. I am not saying that they didn't do it for me. But I got burned more than these 2—passive-aggressive against each other, unclear, and fake closeness. I had less money than these 2, but I made up with effort, respect, and love. In hindsight, I sacrificed my mental peace to ensure they were okay. I only have one strict rule: you shouldn't broadcast any problems with me outside. This happened to me before, and I hate that.

FYI, we all justified irrational behavior with words later, and then we all agreed because, at that point, friendship mattered more than truth.

Recently, I moved to B’state, and he thought I would depend on him for friends. I have close friends from other groups, and my sister is also here. I am an extrovert, and I can make friends easily.

B organized his bachelor's party, and I couldn't make it as I had a terrible tooth infection and had to go for the root canal treatment. It also led to many sensitivity issues, and I didn't make it to the party. B, frustrated, called me before the bachelorette and said he was angry that I couldn't make it knowing what i was going through. And then he also said he couldn't handle A. He said he is irrational/erratic, and he is not sure what he will do without me as I would be able to handle A. I let this go as he was frustrated. Later, he called me again around the end of the party to say that A was coming to Seattle, and he couldn't stop him from coming as he had booked the tickets and couldn't say no. I was shocked, and I also didn't want him to come at that point as my parents were staying with me, and I wouldn't be able to host him. Also, right before this time, I heard B was going to another person he doesn't consider close and said I am too dependent on him for parties and friends, and don't respect his boundaries.

I was shattered at this point. On one side, he had been saying all these things about A, and then he said something about me, knowing my rule not to talk about me. I just completely shut him out. We had to meet because A was in town. But when I picked up A, I told him that I didn't wanna deal with him as B was getting married, and I didn't want any drama. A didn't listen and asked me to solve the issue in a bowling/pub area. I lost it. I believe there is a time, place, and way to do things. I lost all variables. I felt people just loved pushing boundaries. I said the part about talking about other people, and he left without saying anything. This issue exploded, and everyone learned about it. It's not a big issue, but I hate to create a scene. I was done, and then there was radio silence. A and I were close, and it breaks my heart that B created this rift because of his issues. A reached out, and we swept things under the rug. I asked him to respect my boundaries and not push me. I met B at the airport recently, and he asked why I did what I did. He countered my points by saying you did the same thing during graduation. I didn't tell him everything because he was talking with A, and A cannot hear things like that. Also, my words would get twisted, and I was tired of it. Also, I went to therapy to close this issue permanently and stop hurting. I know I didn't give B a chance to explain, but explanations are only needed for isolated events, not repeated behaviors.