Do I tell his gf?

Back story-

A year ago March 2019 me and a guy went out for a night and ended up hooking up, I met him from a mutual friend. After that night he kept reaching out but I wasn’t interested a couple months later I see on IG that he’s expecting a kid I was so shocked and he removed me so I ended up removing him. That was about 6 months ago or so? We still have each other on snap but we haven’t talked until this week he’s been snapping me how he misses my body, I never know when he’s in a relationship because he doesn’t post her unless he has me blocked from viewing the story. Anyways I was never interested in anything more besides hooking up, so I was going along with it and telling me how he wants me blah blah having fun with it. Now I’ve never been the type to be desperate and entertain a guy who’s in a relationship SO I had to ask I couldn’t just risk it and I said something along the line of

“If you’re single than just lmk whenever you’re free :-)”

He replies hours later

“What if I’m not?”

And I said than no sorry but I’ll respect that relationship.

He responds with well we’re expecting but we’re having issues

I’m opened and closed it

Since I stopped it idk if I should still tell his gf/ baby momma?