He stuck himself inside me while I was asleep

We had both been drinking and I think he had mostly sobered up but might've been a bit buzzed still, but I was already asleep and I didn't hear or feel him at all. He told me the next morning that he stuck himself inside me while I was asleep. It scared me a little because I didn't notice at all. He didn't fuck me, he just slid himself in and spooned me while he fell asleep. I woke up and obviously he fell out already.

Just wondering if anyone else had this happen?

He's my boyfriend of 2 years now and I'm not angry or mad, I'm just slightly concerned he thought it was okay lol.