Complex sentence: Angry that Cindy left the motel without telling him, and leaving him stranded without a ride, Dean shows up at the clinic drunk, leading to an intense argument and violent altercation with Cindy's boss, who fires Cindy over the incident.
Split into simpler sentences: Angry that Cindy left the motel without telling him, Dean shows up at the clinic drunk, leading to an intense argument. Dean gets into a violent altercation with Cindy's boss, who fires Cindy over the incident.