Terms & Turns, Sex & Submission is a coin.
Heads or tails?
In book one: Wife awakens husband in the middle of the night, marches him down to the living room, and turns his life upside down. By the next morning he has become her (mostly) obedient, cock-locked "little boy".
"Mistress Mommy" does terrible (wonderful!) things to him, and he struggles to understand this new, precarious, exciting, and confusing balance of power and passion, love and fear...sex and submission.
In book two, the same couple "flips the script".
She surrenders to him; he becomes her master. He's surprised by how smoothly that 180-degree turn is accomplished.
But then, together, they engineer the surrender of her churlish sister - which starts out well but soon goes bad. And when you break something? One way or another: you have to pay for it.
What's love got to do with it? Everything.
As they grapple with pleasure and pain, freedom and responsibility...sex and submission.