Hi OP, I'm sorry this is happening to you it sounds frustrating and infuriating. I don't think you're being abusive although insulting his friend probably wasn't a good idea. It's hard not to lash out when you feel rejected, I know.
His friends sound more controlling than you, and maybe they are jealous that his partner wants to spend time with him. Are they single?
As a gamer myself I want to say I'm on your side with this.
Me and my DP both game together. Or if separately, (or with friends online) we always ask one another if they mind.
Could you suggest he finds a game you can couch co-op? Might be nice to enter his world if you are open to it?
If we're spending time together then no way. We go out and phones are usually off and in my bag. (His choice too)
Tbh I am a keen gamer and like to get in my "me time" but he sounds like a stroppy teenager with a screen addiction. If he won't unplug for you then you can tell him he's made his choice.
It's you or the pixels. Game addiction is real and can be just as problematic as drug, alcohol or sex addiction.
Lastly, so many people are quick to brand gamers as immature and the consoles as "toys".
Really, it's no different to watching tv, losing yourself in a book, a craft, or a sport.
Maybe try to get on his level about this away from the gaming environment, somewhere calm like a cafe or park.
Good luck. If he won't make time for you....
LTB