After watching his girlfriend struggle with an abusive work environment and her self-esteem coming to shreds over a period of time, an unemployed man who feels indebted to her sets out to confront everyone who mistreats her. Things take a turn when all these people start showing up dead and she becomes the prime suspect of the killings.

Thanks for sharing you logline gmffr.

As dpg and Richiev have both suggested, the logline needs some refinement.

A good baseline to use is:

When [INCITING INCIDENT OCCURS]…
A [CHARACTER TYPE]…
Must [OBJECTIVE]…
Before [STAKES].

E.g. When a killer shark unleashes chaos on a beach community, a local sheriff, a marine biologist, and an old seafarer must hunt the beast down before it kills again.

Richiev offers a valuable insight which is that you may need to consider a POV shift for your story, because the "girlfriend" character has a more compelling intention and clearer obstacles.

E.g. “When a disgruntled workaholic is accused of killing an abusive co-worker, she must discover who is behind the plot to frame her for murder with the help of her deadbeat boyfriend.”

That said, if its a buddy caper film perhaps consider structuring the logline to accomodate for that.

E.g. "A disgruntled workaholic and her deadbeat boyfriend must discover who is behind the plot to frame her for murder before XXX."

As Richiev said.

Who is the main character, who owns the spotlight of the story? Who is in the driver's seat of the plot? The man or the woman?

Your lead character seems a step away from the action. His girlfriend is the one abused at work, his girlfriend is the one who is the prime suspect.
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"When she is accused of killing an abusive co-worker, a disgruntled workaholic, with the help of her boyfriend, must discover who is behind the plot to frame her for murder."