Victor Frankenstein decided to create a mate for the creature so he won't disappoint the fiend, also so the creature won't come and threaten him and his wife, Elizabeth, at their upcoming wedding.
A few weeks after Victor completed making the creatures mate.. (Wedding Day)
The creature decided to pay a little visit to Victor to see if he was actually doing his task and he was pleased to see the outcome of his future mate coming to life.
The creature yearned for a specific mate. He wanted her to be ugly and horrific just like him so she can't deny his request to be together since she wont find any other match that'd like her, considering everyone already hates how the creature looks so it'll be the same for her.
Victor had a huge relief the creature didn't make a single entrance at his wedding. Now Elizabeth and him were free from any harm and they lived happily now that they're a married couple.
The creature and his mate also lived happily whilst exploring the world together, moving away from Geneva so they won't disturb Victors life.