Complex sentence: Against his better judgment, he flies with her out of town for one day on an errand, where he is beaten by her boyfriend, and returns too late to make a sales presentation at an important business meeting, causing the loss of a lucrative contract.
Split into simpler sentences: Against his better judgment, he flies with her out of town for one day on an errand, where he is beaten by her boyfriend. Then he returns too late to make a sales presentation at an important business meeting, causing the loss of a lucrative contract.