Talking about Plato and his idea of sexuality and love, the Symposium[0] is worth a read. Aristophanes speech in particular is, in my personal opinion, one of the best thing ever written in this context.
Aristophanes speech is interesting because it presents preference towards either men or women as something innate an immutable in a person. This is quite different from how it was usually seen in antiquity - for example one Roman historian noted that the emperor Claudius was kind of weird because he only was attracted to women.
Yes, usually people writes about the "homosexuality" in the Greece for example, but that's a completely different view: old philosophers used to have their own young boy that gave their body in exchange of intellectual knowledge.
Platone express a completely different view (we won't never know how much the Aristophanes speech was Platone's, and viceversa), without judging.