On Her Master's Secret Service (Masters and Mercenaries Book 4)
Her submission fulfilled her

When Eve St. James married Alex McKay, she had her whole life ahead of her. They were the FBI’s golden couple by day, but by night Eve gave herself over to her husband’s world of Dominance and submission filled with pleasures she came to crave.

His betrayal destroyed her

Worried for her safety, Alex left Eve behind to tackle a dangerous mission. But Alex never suspected that Eve was the real target and her security is destroyed by a madman. By the time he rescues her, his wife has been changed forever.

But when her life is in danger he is her only hope

Unable to heal the damage, Alex and Eve are still trapped together in a cycle of pleasure and misery that even their divorce cannot sever. But when a threat from Eve’s past resurfaces, Alex will stop at nothing to save her life and reclaim her heart.