Complex sentence: Within a short period of time, Tryforos and Tarnower began an affair lasting several years and it became clear that Jean Harris was in the process of being displaced by the younger woman; the two women were 20 years apart in age.
Split into simpler sentences: Within a short period, Tryforos and Tarnower began an affair lasting several years. It became clear that Jean Harris was in the process of being displaced by the younger woman; the two women were 20 years apart in age.