Goddess Andova did not have money to pay someone who did such a poor job for her. She felt that the guy had to learn his lesson the hard way and get what he deserved. And after much thought, she felt that he deserved to eat shit and that is what she made him eat. She was not apologetic about what she had done as she felt that he had also done a shitty job.
Goddess Andova wanted to make her husband understand the dangers of gambling. He had lost some big money recently and she was fearful of their financial future. And that is why she chose to torture him in a way he had never expected before. And that is why the mistress felt that the best thing was to shit on him and forced him to eat all of her poo and drink her urine.
When goddess Andova realized that this guy had a crush on her and he was an ass guy, she knew she had found someone to dominate and take advantage of. She teased him and got him turned on and that made him malleable to her. She then went ahead and she made sure he ate her shit and drank her pee. At first he thought it was part of the fun but then he saw it for what it was.