When madam Tulpan found out that this guy cheated on his wife repeatedly, she had to do something about it because she felt it was wrong. So she acted as if she was into him and when he took the bait, she used that chance to shit on him. As he ate her shit, he realized it was easier to be faithful as opposed to eating poo and being humiliated.
Madam Tulpan has big tits and she does not shy away from using them for whatever she wants to do. And today she wanted to get this guy to eat her shit so she used her big tits to bait the guy. Since he was a tits guy, he loved what he saw and he took the bait. And that is how he found himself eating shit without knowing it.