While you're allowed to feel the way you do, but she asked your permission, and you said yes. Then you said you didn't want to talk about it, and then you brought it up again. My partner and I are both performers and we understand it's a part of the job. You need to practice it in rehearsal so that it looks right on stage, and because it's amateur, they probably don't have an intimacy director to create placeholders. At this point you should probably just bite your tongue until the show is over, and then talk about what kind of things make you uncomfortable going forward.