Girls in Their Married Bliss by Edna O'Brien (1967)
Kate and Baba are both married and living in London. Kate is married to Eugene, the man she once fell in love with and they have a child, but she has an affair with a politician. Baba is married to Frank, who is extremely rich, but also a violent drunk.
Final book in the Country Girls trilogy, and the most disappointing one. Mainly because it doesn't give the full picture and is more rushed. And I definitely didn't like how Kate turned into a suffering woman. What saves this book is that for the first time Baba is the narrator. And she is as witty as Kate is whiny.
I'm not happy that this didn't give any proper finale for the trilogy - just more unanswered questions. I also didn't like that the entire book was set in London instead of Ireland, it lost some of its charm that way.