Final answer:
Frederic Henry's perspective on the war changed due to various factors, including his experiences, disillusionment, and personal losses.
Step-by-step explanation:
Frederic Henry's perspective on the war in the novel changed for multiple reasons, not only because he fell in love with Catherine. One possible reason is the impact of his experiences in the war, witnessing its horrors and futility. Another reason could be the disillusionment with the romanticized idea of war and the realization of its devastating consequences. Additionally, the loss of his close friends and the betrayal he experiences contribute to his changed perspective on the war.