Victor had been consumed by the pressure of his creation, the monster, and that was one thing. To have now to repeat the process also to please the monster was a bit too much for him. Henry had already become enamoured with science, and one could argue that he could take a tragic turn like Victor did. However, that is speculation.  What we do know is that Victor was ready to break the acquaintance with the monster, create the next hideous creature, and try to be left alone. Henry's optimistic view of nature and science was also a pain on his side, as he has seen how evil science could turn things. His behavior only became more erratic and isolated after the incidents took place. It was simply a turn for the worst.