Victor and the monster share many traits, for example, they are both irresponsible. Victor creates the monster and then abandons him, leaving him to figure out who he is, what he is, and how he is expected to live in this society. Victor's indecent abandonment of the creature is like that of a parent who has left his child with no guidance and no family to turn to for help.
Victor's behavior lacks an understanding of his responsibility to the creature, the monster that he strived to give life to, and now, as expected the monster begins to act in an irrational, irresponsible and dangerous manner. Victor's dangerous behavior was to create the monster in the first place, but to leave him exposed, alone and unleashed on an unsuspecting public is the height of irresponsibility.
The monster is very emotional, has deep feelings and longs to be accepted by the soceity that cannot bear to look upon his likeness without reacting in horror. As punishment for Victor's betrayal, the monster systematically destroys all the people that Victor loves. Victor had promised the monster a female companion, started assembling her, and then became terrified at the idea that the two monsters might be able to create little monsters together, and dumped the unfinished body of the female in the river.
In an act of fury and revenge, the monster kills Victor's new wife, both Victor and the monster are left alone, lonely and desperate to punish each other. Victor's quest to stop the monster becomes a game between the two until Victor becomes so ill that he dies.
The monster, desperate and isolated looks upon his creator in his coffin and weeps with misery and loss. Both Victor and the monster have been deprived of real love and acceptance.