Imo, his situation was considerably better then the one of slaves. He was kept not allowed to leave and yes he had sex he did not wanted aka rape.

But not every prisoner is slave. The slaves are present in the books.

Slaves are also killed by Odysseus himself if they had sex with suitors, no regard is made to whether sex was voluntary and odysseus himself claims that sex was rape before (but he just guesses that).

It is not like that story took much regards with regards of rape.