Extreme: The Complete Series by Claire Adams

Widowed father and MMA fighter Justin, just can’t seem to catch a break. He decides to make a deal with a loan shark, betting on himself. When he loses his fight, he has to make another bet.
Four final fights double or nothing.
Anna is his massage therapist and when he tells her he can no longer afford her, she comes up with a plan. He gets free massages if he pretends to be her boyfriend while her parents are in town. He’s always been into Anna so he agrees.
But how long can they deny the actual feelings they have as their façade continues?