I don’t know how to talk to him

Does anyone have any advise on how I can like be able to mention something that is bothering me to my partner? I know he’s someone I’m supposed to be able to talk to and he is but with certain things I just can’t and I’m not sure why. I’ve always had trouble like speaking up when something bothers me or hurts me or causes anxiety and stuff like that which I guess is because of anxiety but does anyone have any idea on how I can like stop that? 😂

There’s something that’s been really upsetting me about my relationship with my partner and I know that I need to talk to him about it because it’s really fucking me up but I just can’t every time I go to bring it up I feel like I’m going to be sick or the words literally just won’t leave my mouth.

I don’t know how to fix this and ig get over whatever the issue is with talking about it like I know that I need to but I just can’t figure out how to do that