G C Scott 
Binding Promises [EPUB ebook] 

When Harold sells his flat, he also exchanges another kind of contract with the new owner: an agreement that involves his complete domination of an attractive, older woman who adores extreme restraint and rope bondage. And so his dark and intensely erotic initiation to the far reaches of control and sexual power begins in the most ordinary settings, with the most ordinary equipment. And despite being shocked at how far Samantha needs to go, can he resist taking her there?