Renegade by K. M. Fawcett
When a rebel scientist and a female gladiator team-up in the Survival Race—a blood sport where the last man alive wins—they unwittingly fall for each other. But the alien masters demand a single champion, and the rivals-turned-lovers are forced to choose between winning their freedom and losing their hearts.
This enemies-to-lovers SFR is book 3 in a series in which each book’s couple finds their happily ever after. No cheating. No cliff hangers. WARNING: Character’s backstory includes sexual abuse.