How do I move on from someone who says he has to work through his issues without an emotionally romantic attachment?

Anonymous
We only dated for 2 months, no sex. He was very attentive and quick to respond to messages and initiate conversations. He told me that he was looking for long-term, and when we talked about apps, said that hopefully we wouldn’t have to deal with them much longer.
On our 3rd date, he had a migraine so I didn’t invite him in. We made out in his car and he seemed excited, suggesting we meet next week. I didn’t want to seem too much so we continued chatting sporadically until next week passed, and I just came out and asked him when he was available.
…He told me he would love to hang out but he had been re-thinking what he could give me, and he wasn’t in the right headspace to give more, emotionally. He had been considering the implications of it, and realised he had things to work through - all the way down to what he wants in relationships, if he even wants one at all. He told me that I was not at fault, gave me compliments, and said he knew I would find someone in no time. He suggested different apps, mentioned he couldn’t date anyone, not just me.
I said if he needs time and space, I’d give it to him. But he said that the idea of me waiting would feel like pressure to work through this faster. It was something he had to do alone, his friends and family had also offered support but he didn’t want it.
We talked about just casual sex but I knew I wasn’t capable so he suggested we put that on hold. He said we could still talk but it wouldn’t lead anywhere and at this point, he just wants to be left alone and suggested I walk away.
I worry about him but leaving him alone is the only thing I can do. His inability to be vulnerable and talk through it frustrated me: exactly as he predicted. It’s his birthday soon, and I don’t want to annoy him but I want to send a message (maybe just 🎂 ), I don’t expect or want a reply. I believe him when he says he’s having issues but part of me can’t move on thinking that it could happen but just not now.
How do I move on from someone who says he has to work through his issues without an emotionally romantic attachment?
4 Opinion