What are the positive qualities in Frankenstein's relationship with the monster?
Sadly, the positives that can be drawn from their relationship could be described as the way Victor Frankenstein is influenced to behave as a result of both his desire to create the monster and his desire to destroy the monster.
Victor initially sets to to create the monster in an attempt to find a way to stave off death. In this way, his relationship to the monster begins even before its creation. He puts great care into building the monster and even remarks,
"His limbs were in proportion. I had selected his features as beautiful. Beautiful! - Great God!" (CH. V).
He worked for close to two years to bring this being to fruition, so the positive quality we could see in this part of their relationship is that the desire to create the monster drove Frankenstein, with good intentions, to attempt something never attempted before. Had the creature not been so hideous, Victor might have realized what an accomplishment the monster was and that all of his hard work was actually successful.
Later, Victor so hates and fears the monster, that he hunts him all over Europe. Again, the monster has brought out in Victor a focus and determination to accomplish something, even if it is the death of the creature. That is not the positive quality, though. The positive quality could be seen as Victor's loyalty to his family and perhaps renewed appreciation of them as a result of the danger that the creature has put them in. In this way, the relationship with the creature has caused the very positive quality of loyalty in Victor to shine.
This is an excellent question, since Frankenstein's relationship with the monster is primarily negative. There are two places, however, I'd like to look for the positives.
First, in Chapter 4, Frankenstein discovers that he can reanimate life once it is dead. He then makes that his primary pursuit. Describing this moment to Clerval, he says that his discovery led to "delight and rapture." He envisions breaking the bonds of death and creating a new species.
While envisioning what this will look like, he says:
"A new species would bless me as its creator and source; many happy and excellent natures would owe their being to me. No father could claim the gratitude of his child so completely as I should deserve theirs."
He continues working through the summer and describes this time as "a most beautiful season." In essence, Frankenstein's feelings toward his creation can be compared to a mother anticipating the arrival of a newborn baby.
Frankenstein's ardor, however, is short-lived. In November of that year, Frankenstein gives life to his creation and the "beauty of the dream" he had felt before is quickly replaced with revulsion and horror. When the monster approaches Frankenstein in his bedchamber, Frankenstein flees.
The next time Frankenstein encounters the creature is in Chapter 10 after Frankenstein's brother William has been murdered and Justine has been falsely convicted. Frankenstein sets out to climb Montanvert to compose his thoughts and sees the creature following him. Frankenstein calls his creation a "Devil" and "vile creature." The creature seeks to explain himself, however, and Frankenstein relents. Frankenstein says,
"I felt what the duties of a creator towards his creature were, and that I ought to render him happy before I complained of his wickedness."
In other words, he feels that he owes his creation an explanation.
The monster recounts his story, and at the end (Chapter 17) asks Frankenstein to make him a female companion. Frankenstein describes that he was moved and could see the justice in the creature's argument. Later, however, Frankenstein will change his mind, which will trigger a destructive retaliation on the part of the creature.
To summarize, there are two moments where Frankenstein exhibits positive qualities in his relationship with the monster: 1) While Frankenstein is in the process of creating new life in Chapter 4, and 2) When Frankenstein consents to hear the monster's case (Chapter 10) and initially agree to making him a female companion (Chapter 17).