What was Victor thinking?

Frankenstein pgs 120-166

            After reading the end of the book, I could only think about Victor. What in the world was he thinking? Victor started on a slippery slope by creating a monster. He made this thing freakishly huge, and had no idea if it would be able to function. After its creation, the monster turned out to be quite modern and had lots of sensible things to say. So Victor and the monster get in a little argument and the monster says he won’t kill anyone if he gets to have a female monster companion. Victor agrees and they leave each other. Victor begins his second creation. One night, Victor is working on this monster-lady and he sees the monster peeking through the window. Victor is overwhelmed and decides to destroy the almost completed monster woman. So the monster tells Victor he will see him again on his wedding night. Now it’s Victor’s wedding night and he is looking all around for this monster. He tells his wife to go inside. Soon after, Victor hears the scream of his wife. The monster wanted to kill Victor’s wife because Victor never completed the monster’s companion. After this sequence of events, I am left questioning Victor’s rationale. He had an ape/monster/hulk type creature threatening him throughout these events, but Victor never listened to the monster, and paid for it in the end.