I'm just re-reading Mary Renault's 'The Persian Boy: A Novel of Alexander the Great'.

As you say about the Greeks and 'Hadrian' that you've just read, bisexuality/homosexuality are just accepted. Lots of major characters (in both history and fiction - or, semi-fictional accounts of history) have a wife and also male lovers....and nobody bats an eye!

(I'm interested in a review piece on 'Hadrian' too please!)