My boyfriend’s best friend cornered me to tell me he dislikes me and makes my BF feel bad about spending time with me and it is driving a huge wedge in our relationship.

First, some background:

I’ve (24F) known my boyfriend, J (23M) and his friend, A (25M) since high school. J and A have been notoriously best friends for as long as I can remember. We have always all been friendly and got along well, having similar groups of friends since high school.

J and I reconnected after college and have been close friends since 2016 and have dated for a little less than a year. We are both very happy together, have great communication and a really healthy dynamic. He lives about an hour away from me (we are both in grad school) so we only see each other on the weekends. J splits his time on the weekend between family, me and his friends - but because we are dating, I usually go with him to his family’s house and sometimes to the bar with his friends. Up until recently, I have really enjoyed the time I spend with A as well. I thought we were getting along well and only had positive things to say about him.

This has all been fun and dandy, but I noticed A was starting to make rude comments to J every time J said we were doing something together (watching a movie, getting food, literally anything). I expressed concern to J but he told me I was imagining things.

One night at a bar, A found me and told me that he thought I was ruining J’s life and taking him away from his friends and that he didn’t like me and could never see me as a friend again. I told J this and he was upset but brushed it off as “just A being A”. Since then, things have only gotten worse. A will make J feel bad if he is doing anything at all when A calls to hang out - saying J is making excuses and lying to A so he can spend time with me. Tonight, A was having people over and he told J it was just going to be them so that I didn’t go - but it turned out he had invited lots of their friends.

J feels bad but won’t do anything about it. I like J a lot and we really get along so well but A is driving a huge wedge in our relationship. Is this worth breaking up over? The drama feels ridiculous - like I am in high school. Any advice?