Is AUTHOR wrong in the post ? POST : TL;DR at the end. Don’t worry

So a little context; my gf and I were really close friends before we started to date. One of her other good friends is her neighbor. She has known him for about 7 years. I didn’t really know him just that they were friends. Eventually we all started playing video games together over the internet. He seemed cool enough. I however am incredibly socially awkward when meeting new people and was not overly friendly with him. 

Eventually my gf and I started dating and after a while he interrogated me to make sure I “was good enough.” I laughed it off and was fine with it. Then though he calls her and tells her he likes her. He claimed to me this was just a prank to see what she said. I didn’t care, we can all take jokes. But he’s kept it up. It’s been 4 weeks now and he won’t let it rest. He is constantly made “jokes” about it and told friends it’s true. 

I became very uncomfortable around him and almost cold towards him. Normally I could over this but he also makes derogatory comments about me, such as when I said “69 damage headshot! Nice” as a joke. But then he replies with “With your right hand forever”

TL;DR My gf’s best friends has made “jokes” about wanting to date her and other stuff. This makes me cold and uncomfortable around him

AITA for being cold around him?