Draka
Wonder Woman
Well, yes they can withdraw that consent anytime they want but as to whether or not it will be honoured is an entirely different story. Sexual intercourse isn't child's play where you say "you can get in now, nope get out, no, get in, no out"etc. That's just childish and immature and defeats the whole purpose of love-making.
I thought the purpose of "love-making" was to pleasure and (ideally in a relationship) show your deepest love for your partner in a deeply emotional and physical way. To not honor your partner's wish to stop having sex, no matter what their reason, would not be pleasuring them anymore, but be causing them grief. I would seriously have to wonder what you consider to be the purpose of "love-making" that would disregard the feelings and physical pain of one of the participants.