Complex sentence: Kim never really loved John as she was really in love with Bob, in frustration of their lackluster marriage, John raped Kim and marital rape was not illegal in those days so Kim couldn't press charges against him.
Split into simpler sentences: Kim never really loved John as she was really in love with Bob. In frustration with their lackluster marriage, John raped Kim and marital rape was not illegal in those days so Kim couldn't press charges against him.