Complex sentence: Free, he tried to begin a new life with Monique but found her dead, with his mother saying it was an accident when she had, in fact, killed Monique to punish Orson for cheating on Alma.
Split into simpler sentences: Free, he tried to begin a new life with Monique but found her dead. Orson's mother said it was an accident, but in fact she had killed Monique to punish Orson for cheating on Alma.