Complex sentence: During the first season, she claimed Levin's virginity whilst he got drunk for the first time, the two then began a long-term relationship, which ended when Levin left to go to an internship in America.
Split into simpler sentences: During the first season, she claimed Levin's virginity whilst he got drunk for the first time. The two then began a long-term relationship, which ended when Levin left to go to an internship in America.