Joel Hammond - Santa Clarita Diet
You're supposed to stand by your spouse through thick and thin, but does that include a new flesh-eating diet? Regardless, Joel still loved his wife and he helped her bury the bodies of her victims.
Emma Swan - Once Upon a Time
Even though their love for each other is true, Emma's feelings for Hook unleashed evil in every sense of the word. Despite everyone's warnings, Emma chose to save Hook which turned both Hook and Emma into The Dark Ones.
Noah Bracken - Roswell, New Mexico
Noah Bracken's love for Rosa wasn't just creepy, it was dangerous. He became a serial killer who used other people's bodies (his wife's included) to do his murdering for him. He was so angry that Rosa didn't love him back, that he killed her and two other innocent girls. But it didn't end there. Over the years, Noah left a trail of bodies all over Roswell.
Vanya Hargreeves - The Umbrella Academy
Vanya had always felt neglected by her adopted father and the rest of her family. After being betrayed by the person she loved and having a falling out with her sister, the hurt made her trigger the apocalypse.
Joe Goldberg - YOU
Joe Goldberg was inherently psychotic, but his obsession with Beck pushed him over the edge. He was so jealous of anyone that would look in her direction, that he ended up murdering her friends before he killed her.
Walter White - Breaking Bed
The entire reason Walter got caught up in meth in the first place, is because he loved his family and wanted to make sure they would be okay. But it ended up leading him down a very dark road and his motives began to change as the series went on.