“Such is my Beloved” by Morley Callaghan - about a priest who befriends two prostitutes, and develops feelings of agape towards them and tries everything he can to get them out of the sex trade. It’s a Canadian novel, but well written.
The Republic by Plato is a classic. If you haven’t read it once in your life, you must absolutely.
“A Handful of Dust” by Evelyn Waugh. It details a devoted husband whose wife gives up on him, the death of a child, and the high life in the early-mid 1900’s.