Gone with the Dead sketch cover

It would be an interesting twist if it was not him that killed her and despite his Zombification, he chooses not to eat her and instead just carries her corpse.

He then finds a good spot to make a grave, digs a hole, buries her, and then proceeds to go on a revenge spree by killing other Zombies with any weapon that he finds as well as low-level superpowers that he gains due to his zombification being different from the others. A Super-Zombie that kills other Zombies, if you will.

In essense, unlike the other zombies, he would be a vengeance-craving Revenant Zombie instead of a flesh-craving Mindless Zombie.