Briar’s Mate by Mia Taylor

Love just moved in upstairs.
Raised in a family who loved him, Briar Pendleson still had a difficult time bonding with members of the opposite sex. In the back of his mind was always the indifferent brunette who left him and his brothers drenched in the rain and the fear that it might happen again.
Safe in his walled existence, his most major concern was the future of his job at Branch Technology.
Safe, that is, until Berlin Matthews moved upstairs.

She was fair and brilliant, a PhD candidate and professor at the University of Oregon. She also had a legacy darker than anything anyone could imagine.
Drawn together by an invisible but magnetic force, the two fall into an uneasy companionship, guided by fate but countered by logic.
When Berlin learns more about Briar than she ever expected, her desire to uncover the entire truth leads her into dangerous and surprising territory.