Why's he being so mean?

I met this guy online. We're part of a community on Discord that chats often, has video calls, and occasionally play games. From time to time, those of us that live nearby meet up and go for drinks, too.
He joined after me, and we hit it off pretty quickly. Have very similar senses of humor/personalities/interests. So much so that he invited me to play a few games together away from the others. We had a great time at first - joked, talked, there was a bit of casual flirting, too, from both of us.
I quickly started to like him, and tried to flirt a bit more. He withdrew, I understood it as a 'no' and sent him an apology. He admitted that he was only looking for a friend but agreed we should probably stop with the alone time.
For a few weeks we didn't speak - I was hurt and we were both uneasy. But it actually got better really quickly. He even brought groceries to my house a few times when I was sick, and when we met as a group again got along fine.

It's been months since the initial confusion, and I was sure everything was great. I went on dates with other people - none that really succeeded - and started relaxing into being sort-of-friends again.
Recently, he's been an ass. It started small at first. He was just a bit grouchy and short. I thought maybe he was having a bad time and left it alone. Then he started commenting on other male friends I spoke to in private, asking "when's your next date with x?" At one point I messaged him to ask if I'd done something wrong. He said no, he was sorry, it was nothing to do with me and he was just a bit sensitive lately. I let him know that he made me feel targeted by is remarks and he apologized again.
A week later we were joking around and for some reason he got irritated out of nowhere and started commenting on my dating habits. Saying I was "better than" the guys I was talking to, that I needed to "have higher standards" and "choose better"... I have no idea where this came from. Sure, my dates haven't been great, but there's nothing really WRONG with any of the guys. They just weren't right for me. There was ONE bad event that I ranted to them all about, but that was back in February. Long forgotten.

If I didn't know from experience, I'd say he was jealous. Considering what happened before, that can't be the case...so why all this? He said it wasn't targeted but I don't see him behaving this way toward anyone else. I've been avoiding speaking to him since that last outburst.