In 1935 she and her husband Diego Rivera were back to Mexico City. She was again experiencing health problems, and her marriage to Rivera had become strained. He was not happy to be back in Mexico and blamed Kahlo for their return. While he had been unfaithful to her before, he now embarked on an affair with her younger sister Cristina, which deeply hurt Kahlo's feelings. After discovering it in early 1935, she moved to an apartment in central Mexico City and considered divorcing him. She also had an affair of her own with American artist Isamu Noguchi. It was a brief but passionate affair; and they remained friends until her death.