Hades and Seph by Eileen Glass

The underworld needs a king.
Another one.
Seph’s family is kind of messed up. His grandfather ate his parents. His father has scores of illegitimate children. His mother grows into a giant when she gets angry—right into the skies!
And all Seph wants to do is get away and be on his own for once. He wants to grow up, which is such a simple thing for mortal men and all the other creatures to do. But when you’re the child of Demeter, Goddess of the Harvest, and Zeus, Ruler of Mount Olympus?
Seph is tired of being treated like a child. It’s time to leave.
But due to the sparring of his cousins over him, Zeus has decided to marry him off. ‘Disagreements amongst gods cause chaos for mortals,’ he says. All of this because Seph was caught kissing a boy.
Well, nothing will happen at Demeter’s villa.
Literally, nothing. It’s run by a bunch of nymphs, who are all women.
All Seph wants to do is find a man like himself so they can explore the world together. But with his mother guarding him and his cousins causing trouble, Seph will have to go on being the ‘baby boy’ unless he wants his father to marry him to someone awful.
From a chasm in the earth, a dark figure emerges…