I don't think the strain on Vlad and Cawti's relationship has anything to do with chamber pots or cooking or cleaning or boredom. They are rich and magically adept. They could pay for a housekeeper or clean the place with sorcery. Both of their lives are exciting (to say the least). I think Cawti got a conscience. She got it, indirectly, from Vlad. She killed him - it was the first time she ever "worked" on a Easterner, and it affected her deeply. She killed him then loved him. Her best friend is a powerful Dragon, basically a professional mass killer (or killer of the masses). These events, plus Vlad's confession to being a Dragon/Jhereg reborn as an easterner, made Cawti THINK about it all. Vlad never bothered - he was too busy hating everything. Cawti stopped hating and started caring. It was the only way she could resolve the hypocrisy of being an assassin, a lover, a Jhereg, an easterner and a friend to the Dragon heir to the throne.