AITA: I told my girlfriend's coworker to leave her alone.
How should I handle my girlfriend's work mate?
Hello, repost from Relationship Advice
J 29M here. I recently started dating this woman A 27F who moved to stay with her brother (my coworker) after her apartment was broken into (irrelevant to the post) in a different city. She didn't know many people so he invited her to join an after work drink with us and we hit it off instantly.
I went to surprise her at her office one day with flowers and I ran into one of her coworkers W 30M, he seemed nice enough as he showed me to A's office but once he realized I wasn't just the flower delivery guy but the guy A has been seeing he became very standoffish. When I asked A about W she brushed if off saying they knew each other in the other city, went on a couple of dates but she said they were better coworkers/friends than partners so she broke it off with him, and a week later he was transferred but didn't know where until she arrived. I made a quip about how many W still had a thing for her to which she laughed and reassured me that there is nothing.
A couple months later, I was at her new apartment when he came over with a "Housewarming gifts" (a bottle of wine and a pizza) when I kindly explained that I was here to take her to dinner and that is gift was greatly appreciated but not necessary, he claimed I was jealous of their relationship and how I was a passing fancy as he was her true future. I asked him to leave and threatened to kick his ass if he didn't back off. He left and text her that I threatened him and that I'm too possessive with abusive behavior. She confronted me about it, I admitted to threatening him and now she is pissed at me for being belligerent. How should I handle this?