I agree that ignoring Anne should lead to sexual frustration/acting out.
Treating the game not as it's coded but as a player might view it...
The original game, especially as it progresses, provides innumerable opportunities for the MC to "go home for lunch" (usually rather than cheat on Anne with someone) to encounter...nothing. It's clear that this is cuckold-indicative, because the game either comments on the absence of Anne or scans the rooms to overtly demonstrate that there's no one home, but there's never an outcome and the game doesn't code for it, other than to avoid coding for the MC's side pieces.
The long-ago post where I pseudo-coded and described how ths might be worked into hotwife, open relationship, swinging, cuckolding, cheating, and even NTR paths described how scenes like these could be used. But it's super difficult and requires a very, very detailed rethink of the game, though I still don't believe it requires re-rendering. Maybe a few additional scenes. Still, it's not the revamp and should, at this point, be ignored.
I wrote that post long after Mircom3D starting rewriting, and I think the revamp will be a lot simpler than what I suggested. Which is perfectly fine. I just hope for a more sensible game, and the dev seems to want that as well.