FP replaced me

My fp has been my best friend of 3 years, pretty much since I met him. We've been through a lot of different friendships and hardships and it's always been just us at the end of the day. He's dated people in the past, so I don't have a problem with him dating, but the way he's been treating his boyfriend is getting to me. He's doing all kinds of things with him that he never did with me. They'll sleep on call every night, but when we call (which we haven't for 2 weeks now so that is getting to me too) and I fall asleep, he'll leave and tell me "there's no point in me being there", and I get it, they're dating they'll do things he wouldn't do with me, but he was doing this with them before they started dating. So what made their friendship so special that he'll do things with a friend of a few months but not with a friend of 3 years?? Also he's just been completely blowing me off for his boyfriend. I'll text him and he straight up ignores me until he feels like responding, but I know he's responding to his boyfriend. I can't prove it but I know he talks about me to him poorly. I just don't know what to do because it's really bothering me but I told him he should prioritize his boyfriend over me but I didn't think it'd mean forgetting about me. I find myself pushing him away more and more but I really don't want to do that but I don't know what else to do, I can't handle being treated as an after thought, especially not by him. I also can't talk to him about it, so what do I do? What would you do if you were me?

(Also this isn't the whole story before you call me dramatic, I just don't feel like typing it all out.)