Am I right to be creeped out?

A friend told me yesterday that a year and a half ago, we had sex. He said ‘i think it’s time you should know, we had sex’.

Apparently, on a night we were both very drunk, I came onto him and we did it. While drunk I apparently said to him: ‘I won’t remember it, so remind me’. He kept it hidden for over a year and says it’s because he thought I wouldn’t want to know.

This feels very wrong. Am I overreacting? Why would he think I wouldn’t want to know? I have 0 recollection of this ever happening.