Under His Control by Claire Thompson

Sold to a Master she shouldn’t want. Maybe he’s exactly what she needs…
When Ellen signs up for an Enclave binding auction, she hopes to be won by a Master who shares her happily-ever-after dreams. Instead, she’s paired with an ex-military special ops bad boy who is definitely all wrong for her, even if everything he does feels so right.
Damon has a dark past he’s never faced and a future with no place for love. A submissive who’s looking for Master Right should send him running for hills. But something about Ellen gets under his skin and just won’t quit. Fortunately, their Master/slave contract has a built-in escape clause. At the end of seven days, he will walk away, no strings attached.
If only it were that easy…