F22 My boyfriend's M21 chronic bad breath is impacting our intimacy and I don't know what to do. Advice?

I discussed the matter of his breath long ago and a bit less (twice) with my boyfriend. It's been two years of us together, and the issue I thought was maybe fixed at times mostly isn't. I don't feel like chewing gum is helping because when he licked my neck a week ago, it left a bad smell. I remember the first time we said "I love you" and we kissed, I remember holding my breath and shrugged it off as bad timing. It isn't always an issue, but I've realized that I'm having a hard time living like this.

It's been turning me off from kissing him. He has asked multiple times why I'm not kissing him and why I'm pulling my head away, and I didn't want to answer because we have discussed this matter twice. The second time, he said that he'd been told that it's nothing he can fix and it can't be cured, as doctors told him. But I can't live like that. It makes me not want to kiss him. I'm holding my breath to not be taken aback each time or praying that I don't have to hold my breath whenever I feel a kiss coming.

I don't know whether to chat with him again or to break up with him. I love him, but to be honest, "the discussion" (a longer chat) did happen twice, but I've mentioned it/talked about this matter more than twice with him, and as you can guess, it was never comfortable for me to stir it up even though he did give me space for it. I just don't want to hurt his feelings by telling him over and over again that it's bothering me.

Besides that, I've noticed that a few times his pants have had a smell near the private area. I've never discussed that with him, but that has bothered me too. I've gotten to know that he doesn't wipe his area after peeing, as (him saying) no guy does that and his area doesn't need paper wiping, "it dries on its own." It was a discussion, let me say, but I realized I couldn't change his ways.

The relationship was great, but lately it has been a bit rocky because we've been having a hard time navigating through conflicts and understanding each other. We haven't argued for some time now, but that, with the kissing being hard and me having to hold my breath whenever he kisses, has been making me question if it's a relationship I should break up with him over or stay and try to work through it. We had something great, and he's willing to walk through it, but at the same time, how many times can I tell him to take care of this breath?

Here's the grammatically corrected version:

I've been a bit too blue lately and I haven't seen him for a week. I've not been properly going out, but in a way, I feel like I've been avoiding him since the last time (when he licked my neck, it smelled bad). I love this guy a lot, but I don't know how I've been feeling about him because of this and our previous fights. He texted me that he misses me a lot, loves me a lot, sweet stuff.. I text him back "me too," but the last incident has thrown me a bit too off. I'm very conflicted and feel too awful and guilty as a person for feeling this way and for even writing this post.

TLDR

Boyfriend's chronic bad breath is ruining our two year relationship.

My boyfriend's persistent bad breath (he claims doctors say it's incurable) is making our relationship hard for me. I'm turned off and uncomfortable from trying to address this, despite loving him. I'm questioning whether to stay or go.