My thoughts after review:
Only thing that comes to my mind is that he was a bit scared of jamming flop because he was oop and didn't want two callers so he decided to flat call. And when we were HU and the turn was blank, he decided to raise me.
Is my thought analysis correct?

Anyway, how would you guys rate my play? Should I have just checked flop? I ran some simulation and I was getting good odds to call his raise on turn, and I would definitely have folded river if the board paired even if I hit my flush, so I don't think that was a mistake.
Thanks!