My Husband Likes to Watch: Regency Cuckoldry
C.P. Waterman

Barclay reveals that he is aroused at the idea of watching a couple having sex, and decides that he would like to see his wife playing the whore with another man. She arranges a deal with her old friend, and they perform in front of her husband; this unconventional arrangement is fraught with lust and titillation for all three participants.
Eleanor takes this opportunity to explore his sexuality and finds there is only one way that he can climax with her; he designs and creates device by which she can penetrate him...