Read an old Harlequin novel, probably in the 80's, or early 90's... but the book may have been older. It was about a model named Suki, who was thought to be having an affair with a man (but in reality, that man was her long lost half-brother). Any help you can give in finding this book would be wonderful... it's been bugging me for years!

"I want you to become my mistress!"

Suzanna was stunned! She was no longer the naive seventeen-year-old who had thrown herself at Pasquale Caliandro; now she was renowned model Suki. Other men might proposition her, but Pasquale had bitterly rejected her seven years ago. True, the electrical charge between them was as strong as ever, but what was that without any tender feelings? He must be mad or have a very warped sense of humor! But, she thought, Pasquale never joked about business - and being his mistress was business...

https://www.goodreads.com/book/show/...tress-material