He's obvs going to tell her he's with Yoriko and that's why he's apologizing, but as usual it's expressed in an actively misleading way to create expectations and affect the characters with misunderstandings
If you look at the raws (authors twitter + pixiv), at least to me, I don’t think any NTR goes on, though that’s coming from an English-only speaker. I could be wrong but from what I can piece together I think we’re safe boys
WTF!!! IF THIS DUDE SERIOUSLY GIVE IN TO THAT "TEMPTATION" THEN HE IS JERK!
BUT IF HE JUST REVEALED THAT HE'S DATING THEIR SENIOR THEN IT'S ALL GOOD...