Victor says he loves Elizabeth. They have been sweethearts since childhood. However, when he leaves to the University of Ingolstadt and makes his monster, he totally cuts off contact with "the woman he loves." Of course, Victor also cuts off contact with the rest of his family and his best friend, Clerval. He loses so much contact that Elizabeth writes him, asking if he has found another love. This shows how self-absorbed and obsessed Frankenstein is. When he finally marries Elizabeth, he knows the monster has promised to be with him "on his wedding day" but he foolishly leaves her alone while he checks out the downstairs of their honeymoon lodge. Thus, he does not seem to be a very clever or thoughtful lover and Elizabeth is the one who suffers from his lack of total commitment.
Elizabeth was less a character than a plot device. He spends all but a few days of his adult life avoiding her, in his lab, but he writes her many passionate love letters.
Women aren't really a part of Victor Frankenstein's life. We barely see his mother in the third edition (and not at all in the first edition). His life's work involves making another life without a woman's participation. There is a paucity of female characters in the novel; if Elizabeth is just a plot device, poor Safie is barely even that! This is an inconvenient fact for the many grad students who want to hold Mary Shelley up as a feminist icon: the only character she related to was Victor.
Victor Frankenstein was a multi-dimensional character. We see that he is obsessed with death and the reanimation of human life. This whole obsession rules his life. Being married to Elizabeth can actually been seen as the human side of Victor. The way Victor describes Elizabeth, shows us that he has real feeling for her, although he leaves her at many times.
"She was docile and good tempered, yet gay and playful as a summer insect. Although she was lively and animated, her feelings were strong and deep, and her disposition uncommonly affectionate. No one could better enjoy liberty, yet no one could submit with more grace than she did to constraint and caprice. Her imagination was luxuriant, yet her capability of application was great. Her person was the image of her mind: her hazel eyes, although as lively as a bird's possessed an attractive softness. Her figure was light and airy: and though capable of enduring great fatigue, she appeared the most fragile creature in the world. While I admired her understanding and fancy I loved to tend on her, as I should on a favorite animal; and I never saw so much grace both of a person and mind united to so little pretension."
Although Victor may have loved Elizabeth, his love seems to come more after her death. His obsessions ruled his life and in the end, cost him his wife's life.
Elizabeth was a foster sister to victor, as they got older they relationship became more serious than what they were at first. victor had strong feelings for elizabeth, he then asked her to marry him.