Victor agrees to create a mate for the monster. He works hard on her but eventually ends up destroying it. He was worried that she would not want to live in solitude and they would reproduce. These fears are rational however, I believe he destroyed her out of selfish reasons not noble ones. I think he was worried about feeling more guilty and sorry for himself than he already does which is why he destroyed her.
Were his actions justified? Understandable yes, justifiable maybe not. He not only made the monster angry but he endangered everyone close to him by choosing to destroy the monster’s would be mate. It is obvious that Victor can not control the monster and when the monster is denied something good it resorts to violence. As the creator I think he has an obligation to make the monster happy to an extent. He did not befriend his creation in the beginning, instead he abandoned it. The least he could do is give it a little happiness since he was the once who created it.
I can not help but feel sorry for the monster and think negatively about Victor. The monster never asked to be created but it was. Victor played god by creating it but chose not to take responsibility. Instead, he ran away and as a result his loved ones keep getting hurt at the hand of the monster he created. I feel that the very least he could do was create a mate for it since he is in this deep.