WTF is going on

My boyfriend and I have been together for 2 and a half years and I'm not really happy anymore. I need advice on if my thoughts of breaking up with him are valid. Like everything is ok it's just I feel like I'm not a priority to him like I just get what's left. His friend is over every weekend all weekend all they do is fish the entire time I'm not invited to go. I've already talked to him about this twice and honestly I just dont feel like me anymore. And it's just really hard because this is my longest relationship of my life and we live together. But the thought of marrying him and having kids makes my chest feel tight. I seriously think I'm done and it just kills me because I dont want to hurt him or see how upset he is going to be. It's just I'm a mess and honestly i just want to be able to breathe again any advice or reassurance would be great.