Sucker Punch. Super Short Super Hero Instalove Romantasy, #2

Peter Strong uses his super strength to fight for his life and liberty.  Brynn Davis fights for money. They were both enhanced in the inhumane laboratories of the Aethor Institute and then left to die when the Institute imploded by sabotage and treachery.  Peter became an investigative reporter, determined to get truth and justice for the supernatural community.  Brynn hit rock bottom and pays the bills by fighting in an underground MMA club.
Peter is a Pollux strain variant, known to be reckless and unstable.  Brynn is a Castor strain, who are more strategic and tend to shun confrontation, which makes Brynn's martial leanings a special interest to Peter's research.  Not to mention that Peter thinks they may have literally been made for each other in the lab. Before it's destruction, the Aethor Institute transformed the Castor and the Pollux test subject's DNA so they have one perfect match.
 And bonding with the fated mate will allow their powers to grow to their ultimate level-for good or for evil. With the world watching, Peter and Brynn are destined to be together, but there are forces at work that want to destroy them and their love.