I am looking for a title of a romance novel I read years ago about a women's version of a gentlemen's club. I think the title had the word butterfly in it

Could this book be simply entitled 'Butterfly' by Kathryn Harvey?

This novel is about a mens club above a mens store where rich and affluent women are invited to attend in order to act out their erotic fantasies.

You will find more about this novel at:

Butterfly, Kathryn Harvey, Book - Barnes & Noble

I hope this is the one you are looking for.

Poseidon