Why am I so attached to someone who has never been consistent with me?

Why am I so attached to someone who has never been consistent with me?
I’m 42F and recently separated after a 10-year relationship. I’ve reconnected with a man I had a brief romantic/sexual relationship with about 10 years ago.
The history is complicated. He ended things back then, but over the following years he came back several times, wanted to see me, and at times looked for me himself. It wasn’t simply about sex — there were times we met or wanted to meet without anything sexual happening.
We recently reconnected. He was quite engaged at first: he moved the conversation to WhatsApp, called me for about an hour, asked about my love life, told me he was separated, and suggested getting a drink when I’m in town . I’m going there next week.
And now… silence.
I haven’t chased him and I don’t intend to. But I’m surprised by how much this affects me. I’m very attracted to him, and I think I became emotionally invested much faster than I would have liked.
What I’m struggling with is that I don’t even know what I’m looking for advice about. Maybe I’m trying to understand why someone can repeatedly come back into your life, clearly seem attracted/interested, but never actually build anything with you.
And maybe more importantly: why does his uncertainty affect me so much? Why do I seem to want to be chosen by someone who isn’t choosing me clearly?
I’m not sure whether I should simply let this go, meet him if he suggests it, or take this as a sign that this dynamic is bad for me.
I’d really appreciate perspectives from people who have experienced something similar.