This may be The Gap into Conflict: The Real Story by Stephen Donaldson. The cover was mostly red or red/orange - like an explosion.
To quote Wikipedia:
On the way back to Com-Mine, Angus activates Morn's zone implant, allowing him to repeatedly rape and abuse her. Unwittingly, he also starts to form an emotional attachment to her.
Back at the station, Morn makes contact with another pirate — Nick Succorso, captain and owner of the ship Captain's Fancy, who she sees as a potential rescuer. She aids Nick in framing Angus for stealing station supplies, and Angus is arrested. Before he is taken away, though, Angus gives Morn the remote control to her zone implant, in exchange for her silence. With the control in her possession, Morn is effectively a superwoman and is able to disregard fear, pain, or fatigue; but by accepting the control she is also complicit in Angus' crime against her.
Morn leaves with Nick in his ship. Nick, however, turns out to be every bit as nasty as Angus.