With the rest of your story, your friend just seems like he’s overly pedantic. It’s not like you were trying to pick up anyone who really had to know if the first conversation the exact reason you are single.
He seems like they kind of person who has to let everyone know “well, it’s his second marriage” as if anyone cared any more.
While I would agree that technically you are single…I think it depends upon who you are speaking with.
For instance, my idiot younger brother has been married and divorced EIGHT times!
So, if I were a woman stupid enough to date him, I think it would be more important to know the dickhead has already screwed up 8 marriages than simply want to know if he were “single” right now.