I [25F] am having trouble understanding his [26M] hot/cold behaviour...

I [25F] have been hanging out him [26M] for 8 months. We've slept together a few times and although we aren't exclusive, I know that he isn't seeing anyone else. We also used to date a few years ago (2 year relationship and 2 years of no contact). Because of this we are unable to define our relationship. He has said that we are more than friends... but "it's complicated" is the best way to describe us. I don't think he wants a relationship with me because he's worried that he will change his mind and end it (he ended it the last time).

Most of the time he keeps in contact, tries to make plans and after I see him, gives me a goodbye kiss. The last time I saw him he avoided kissing me on the lips but definitely didn't keep his hands to himself (although it didn't get anywhere)...and when he was leaving he said that wanted a hug (which was basically saying "not a kiss"). I didn't push, but when I got home I invited him to hang out the next day to which he politely replied "sorry, I can't. I'm busy :) ". This is ok, but he usually says more, or suggests a different date.

If this were the first time he has reacted this way, I wouldn't be so confused. I would assume something happened... he's not in a good mood... I would simply accept it and wait. But this happens every so often... (maybe every 1.5 - 2 months?). Now I know that he won't talk to me for a while, and if I message him - his answers will be polite but short. After a week he's usually texting/calling again. It's very confusing and I don't know whether he is uncertain and pulling away but then coming back? Or is he trying to make me come to him? make me more interested (he's the type of person who likes to think of psychological ways to deal with people...)? or is this normal? (we see each other once every one or two weeks. and we text most days but not every day.)

His hot/cold behaviour is confusing and I'm not sure what it means or how I should handle it.

TL;DR He pulls away from me for about a week, every 1.5-2 months and then comes back. We aren't dating but we have some sort of feelings for each other. I'm not sure how to understand it, or maybe it's just a normal thing?