My (32F) old friend (34M) reached out to confirm to his girlfriend we are not having an affair… I feel super weirded out not sure what to do

Burner account cause a lot of friends know my main and I’m super embarrassed

As title says. I have a friend whom I use to have a huge crush on. He’s pretty cute and we share a ton of super specialized hobbies. We hanged out quite a bit a couple of years ago but things never went nowhere. He never made a move on me. Eventually I had to move for work and we stopped hanging out.

That said we never lost touch via phone. Every few months I’d reach out to him or vice versa. We tried to hang out several times over the past couple of years but one of us was always seemed to be out of town.

Anyway convos had been picking up this month quite a bit. He kept on asking me to go out for the weekend. I thought it’d be fun. Then today out of the absolute blue he calls me and when I pick up he says something like “hey I want you to confirm that we didn’t have sex this past Sunday, you are on speakerphone with my girlfriend of 2.5 years”

First of all, I had no idea he had a gf!!! Second of all, I did nothing wrong and had no idea we were having an “affair” or were suspected of such.

He caught me totally by surprise (no text no nothing) and I kinda froze so I just said “yup confirming I haven’t seen you in 2.5 years and we definitely didn’t have sex on Sunday.”

Wtf. This feels truly bizarre. No idea what to do now. Should I reach out back to him? To her to reassure her? Should I just disappear? I feel like people are talking about me and it’s not my fault