Complex sentence: He initially considered his relationship with Rita to be part of his disguise; however, by the end of the fourth season, Dexter had fully evolved into a family man and wished to rid himself of his self-titled "Dark Passenger".
Split into simpler sentences: He initially considered his relationship with Rita to be part of his disguise. However, by the end of the fourth season, Dexter had fully evolved into a family man and wished to rid himself of his self-titled "Dark Passenger".