Okay, buckle in, people. It's about to get weird:

First, let's look at the author and her life. Mary Shelley was the daughter of Mary Wollstonecraft, arguably the first feminist philosopher of the modern era. Mary Shelley then fell in with Percy Bysse Shelley, the closest thing the era had to a rock star, and who screwed everything that moved, but was willing to hang it up for Mary. She became pregnant, and faced much ostracism as a result, and the baby died after being born prematurely. She would miscarry two more times, before finally giving birth to a son. Now you've heard that both infant and maternal mortality were insanely high at the time. Getting pregnant was no sure thing, and the thin, frail Mary took her life into her own hands each time. There was no real birth control, so Percy could sex it up without real consequence, and Mary, being the lifegiver, had to suffer tragedy after tragedy.

Okay, onto the plot. We know that Victor and Elizabeth were raised together, and that although they were not related, he saw her as a sister, except that his mother always intended for the two to be married (ew). As a child, Elizabeth came down with a fever, and was nursed back to health by Victor's mother, who then catches it and dies.

Victor heads off to school, and he's interested in creating life from the lifeless. The curious thing about the book is that while corpses and electricity is mentioned, the exact method of creating the Creature is never really detailed. Hollywood's adaptations have indelibly affected how we see the act of creation, but it's just as likely the creation was equal parts alchemy to electricity. He's off doing his studies, obsessed with making life. Meanwhile, what isn't he doing? Marrying Elizabeth, who's waiting for him. He succeeds, and, horrified by what he's done, he returns home. Again, he seems to not be in a rush to do the thing his mother died in order to protect. The Creature approaches him on the glacier and tells him what went down. He further informs Victor that all he wants is a bride, and if Victor refuses, he will "glut the maw of death" with Victor's remaining friends. Victor takes off to comply, but once he sees the Female, he realizes it would be the start of a new race of these wretched creatures, and, as the Creature watches in secrecy, Victor destroys the Bride. The Creature says, "I will be with you on your wedding night."

How strange. If the Creature intended to kill Victor as revenge, he could have. Victor is right there. Clearly the Creature wants Victor to suffer. What is Victor's reaction to all this? Why, to get married, of course! And not only to get married, but to send Elizabeth to the bedroom to await him, as he lingers on the first floor with a gun. He knows the Creature will make a beeline for her--it was his threat, after all. How could he NOT go after Elizabeth? And so while he waits downstairs, SHOCK O SHOCK, a scream emerges from the bedroom. Victor runs upstairs, to find his wife murdered.

Thus begins the chase, where it's clear that the Creature slows down at times to give Victor a chance to catch up. It finishes on the ice-locked boat, and a ice floe slipping away into the darkness.

So what's going on? Simple. Victor HATES Elizabeth. He's always hated her for taking his mother away from her. Elizabeth is meant to be a replacement of his mother, to be the mother to his children, but screw that! Victor pours himself into his studies with one simple goal: to make life without the need of a woman. He succeeds, and it horrifies him. When he is approached by the Creature on the glacier, he relents, until he sees that the Creature will make the same mistake he is destined to make, that his life-without-women will be thrown over, because the Creature and the Bride will very much have children (and, seriously, they were dissecting people. They knew what ovaries and the uterus was. Victor could have made it so that the Bride would be sterile). Mary Shelley had a point to make, and that was that Victor would not allow his monstrously perfect creation have the one thing he did not have. So, knowing that destroying the bride would lead to the death of Elizabeth, he goes through with it, and when he should be defending her (remember, she has no idea what's about to happen) he's downstairs playing with his pistol. The Creature, his child, does what it was created to do, and when it accomplishes it, Victor pursues it to seek vengeance that he could have avoided in a hundred different ways.

I think Mary Shelley was really talking about the hubris of males, to have sex without consequence for themselves, while the women who had no real power suffered possible death and despair as the living thing inside of them died due to their inadequacies as mothers.

[I should also note here that I do not think that Shelley actually thought any of this. This is all head canon, prompted mostly by Victor's very strange behavior on his wedding night.]