How to break up with my (29F) partner (31M) when things aren’t bad but they’re also not really good?

Ok I know this sounds absurd and the obvious answer is “just break up,” it just feels easier said than done. This is my longest, most serious relationship and in all my past relationships I’ve been the dumpee.

For background, we’ve been together 4 years and have lived together for 3. While we’re a good team in terms of sharing household responsibilities, spending time with friends, and traveling, and we don’t really fight, I’ve increasingly realized that we also don’t really have fun when it’s just us.

I’ve tried pushing to do more together in our down time without much success. On the rare occasion we’ve played a card or board game, it feels like he’d rather be getting a dental cleaning than hang out, and it feels like we don’t have much to talk about beyond work and current events. Also while we both are funny in our own ways, we rarely if ever make each other laugh. When I convince him to go out to dinner (also rare), he’s overstimulated by the noise and we get the check as soon as we’re done eating and go home. However, he has no problem staying out late at bars with friends and when I’ve asked what the difference is he’s said it’s a different mindset because it’s partying rather than dining out?

I’ve raised these issues periodically for about a year now and have recently told him it’s a dealbreaker if we can’t find more to do together. Honestly though I just don’t think we’re that compatible, and I feel guilty every time he alludes to a future together and confused that he doesn’t seem to want more for himself in a partner. I don’t want it to seem like a breakup came out of nowhere or anything but every day I get closer to blurting it out. I would so appreciate any advice on how to approach this.

TL;DR: my partner and I get along fine, just not in a way that I want to spend the rest of my life, and also not so poorly that it’s obvious a breakup is needed. I have never been the dumper in a relationship and am seeking validation that I’m doing the right thing and advice about how to go about it.