You don't even know who is neighbor and who is aunt, who is mother and who is landlady.
No no. You said she had her turn.. but wasn't that sex scene locked behind a "cucking" option? So if we pick no cucking she doesn't have a sex scene. MAYBE. I dunno. But maybe this is why the guy who mentioned her waits for sex with her because he picked the no cucking option and there was no sex with her then.
I am not positive whether this is the case or not you see as i went with the cucking option but i do noticed that if picked certain options some girls do not appear at all much later and some scenes never happen even with ones who do appear.
So my bet is, the guy picked the option that excluded the sex scene with that neighbour lady.