I'd read one of the novellas, The Conjugal Clock, on another site. I was impressed with Ms. Zacharias' abilities as an author then, and emailed her about it (alas, the addy was no longer valid). The other two novellas contained within the anthology "Wives in Service" serve to confirm my first impression of Zacharias as a damned good writer.
In 'The Conjugal Clock,' the protagonist marries into a family that has a generationally successful history of using an unusual method (and device) for ensuring marital bliss.
'The Baby Machine' concerns a young woman who is determined to do her exponential utmost in fulfilling that biological imperative that drives every living species.
'The Man in the Middle' is a tongue-in-cheek tale featuring a man, the narcissistic woman that (thankfully) got away (but later tried to come back), her husband, email, sex--oh, I do hope you're intrigued!
This short anthology is worth far more than the price. Do read it.