It's one thing to be interested in somebody's sex life and/or happy your friend scored.
Here, I feel like it's used as a punchline with Huntress the brunt of the joke, and to me the whole exchange did make Ollie seem extra creepy to me.
I started thinking what other 'hero' could/would replace Ollie in that page and say those words, that way. Couldn't come up with anybody DC top tier.
I can see, say Kon, maybe, being congratulatory but it'd be whoa, dude! Or somesuch. And Kon is a lot younger, more naive. He'd be happy for the guy, whatever. Kon would be less surreptitiously smarmy while being overtly smarmier, imo. Plus, Kon's not a married former mayor talking about one of his wife's former coworkers (not strangers, and I think that flavors the tone too.) To his best friend who is obviously uncomfortable.
To me it comes off as particularly smarmy, and I have to wonder if that's on purpose or what. Ollie isn't even portrayed as picking up that his bff of a million years is less than comfortable with the discussion.
I don't even see Roy as doing that with say... Dick--congratulating him in that way on a threesome with women they know--I think he'd use different words--and if he did, and if Dick was uncomfortable, he'd figure out fast and tone it down or stop.