The dynamic between the couple in the first chapters worked for me, even though I would have given the player more options to intervene, to stop or cancel certain events entirely.
The overall impression for the game in its current state is good, so I won't comment on the positive aspects and go straight to the parts that I find weren't solved satisfyingly.
Dynamic with his father
Up the point that Martin is introduced, it's a classic cuckold game. That changes whit the bathroom scene entirely. Even if the MC makes clear that both having sex wasn't originally what he thought the outcome would be, Anne has sex with Martin a second time (after him saying no) and then even cheats on the MC with Martin despite him opening up to her that his father had stolen his girlfriends before (and now his wife).
I think Anne's cruel behavior, even if this route starts with the player's decision, crosses the line of cuckolding and destroys their relationship for good. This couldn't have been what the "official" cuckold route was intended to turn out, or was it?
On a second note, it's odd there isn't enough exhibitionism or outdoor sex with other people watching, especially in the first chapters. That makes the game very one sided. Bits of information about their target's spouses reaction/suspicions would also make the game more vibrant.