Can’t get over my ex

I’m completely new here but hoping some other people could give me some clarity.
I was with my ex for 4 years. We lived together. Planned a life and future together. Then he starts pulling away. Long story short after confronting his change in behaviour he seems lost and we break up.
It’s been over 5 months and I can’t let go of hope. We ended really amicably. He messaged me to check in quite often but just wants to be on his own. He begged to come to my birthday as he wanted to be there and we meet up occasionally – nothing more just conversation. He’s said he can’t see us being together but he can’t see himself being with anyone but me.
I get that he needs to be on his own. He might have some wild Oates to sew and I understand that – but because there has been absolutely nothing concrete splitting us up. I can’t get out of my head we’re going to work out. We had our problems, it wasn’t perfect, but he pulled away when we had 6 months of absolutely no drama. Finally getting to a content and comfortable place in our lives.
Am I crazy to hold on for him to go through his crisis? Or is he just trying to spare my feelings with the ‘alone time’. I’ve asked him a couple of times to be honest if there was more and he hasn’t.
It’s just driving me crazy because I can’t move on when I’ve still got hope but I want to because I’m not naive to the fact we might not be end game.
I guess I’m just wondering if anyone here has a similar experience and reaching out for advice and opinions. Thank you.