Complex sentence: Keller explained that Hughes and Bacon had started a sexual relationship before the contract was signed, and that this continued for some time, however Hughes later discarded Bacon, both professionally and sexually for the actor Jack Buetel, who was subsequently cast as Billy the Kid.
Split into simpler sentences: Keller explained that Hughes and Bacon had started a sexual relationship before the contract was signed, and that this continued for some time. However, Hughes later discarded Bacon, both professionally and sexually for the actor Jack Buetel, who was subsequently cast as Billy the Kid.