It's not just the voyeur aspect of cuckqueanry; the emotional masochism is the defining element. Here's one quean's description that can be applied to almost all cuckqueans:
“I am learning that on top of all my other kinks. I am with out a question of a doubt an emotional masochists. Very much wanting to be a cuckquean: meaning I must accept the fact that my master can fuck whoever he wants, whenever he wants, with or without telling me.To know that he may choose to point out ways she is better or may choose to tell me nothing at all. I know that his pleasure comes first and their is no way I could fully pleasure him just myself. That he deserves variety and it is his right to do so. I find this to be a wild turn on to know other women are enjoying his cock/tongue while he is enjoying them all the same.”
I have additional info about the fetish as well as copious content on cuckqueanry (check out the alliteration, huh?) on my blog http://www.closetquean.com/about/
Gotta run - work.