I feel the same way. 4 years ago I met a guy who, I didn't realise, was one of the kindest sweetest men I'd ever know. I knew him from high school. He absolutely cherished me. He would always offer to help out with errands when I couldn't do them alone, he'd come over just to make me cups of tea when I was sick, he could hold a conversation, he never once pushed for sex in the 6 months we were seeing each other, he was witty, smart, fun, musical, and hygienic (it sounds dumb, I had no idea how gross scrotes could be). I had no idea how rare it was to find a man with even half of these qualities, he set the bar so unimaginably high that every guy I've talked to since is just… blegh. I honestly struggle to get through a single date, and it's because of him.
We ended things because I was in a bad spot. We hadn't seen each other for a few weeks, and it was entirely because I felt so low and stressed that I wanted to be alone. I withdrew from the world, and I don't know why. I didn't say I was depressed, but he could tell because he was trying to cheer me up in his sweet goofy way. He kept bugging to see me, he said we should go out for coffee somewhere - in my head I thought he was just annoying me to get in my pants because that's all anyone wants, but I realise now that he was probably just trying to get me out of my room. He eventually convinced me to at least have a phone call, but I really didn't want to speak to anyone at all. He picked up the phone with a smile in his voice, saying how happy he was to finally hear my voice again, when I very coarsely asked why he was annoying me so much because "we're not girlfriend and boyfriend". We hadn't really discussed our relationship status, we were friends, but we were also flirty. There was silence, then he croaked out, pathetically, "do you think we could be?" when I flatly replied "no". Then there was silence for a bit, which I broke by saying I needed to go, and I hung up the phone. We stopped speaking after that, actually I blocked him because he tried to call me again, and again, and again. In my defence, it was annoying and I already felt bad enough, but I probably should've just picked up. I did genuinely like him, and I don't know why I acted the way I did (beyond mental health reasons). I didn't unblock him for a long time, then when I eventually did, he told me to leave him alone. I fucked up the best deal I ever got, and I can never get it back.