Shes biting your head off anytime you mention 'intercourse','sex' or 'no clothes'. These seem to be real hot triggers for her. (Something to mention to the therapist, perhaps). Perhaps the sensate focus exercises are being resisted because they could lead to closeness - and as you've pointed out before she fights if closeness is possible.
You might want to extend the sensate focus programme - instead of being 3 weeks, make it 9. Start with foot massage in week 1 (for both of you) then gradually introduce other non-threatening touch on a week by week basis. (Hands, head, back and so on). It's important for her to reciprocate though.
As for doing the exercises\videos, perhaps you could say 'I'm going to watch the X video now, you can join me if you want.' Make it really low key and non-threatening - but you're showing leadership.
You say in your first post that it got a lot worse, recently (last couple of years). Did something dramatic happen?
