Companions ask, you say no, and that's the end of it. (With the exception of Astarion who can potentially bring it up twice.) A lot of women wish it were that easy in RL to stop unwanted advances.
Is it? My first playthrough, when my character turned down Astarion a second time, he gave her a speech how she is saying no, but he knows she desires him. That is not how I'd like to see it in games, as a woman.
