Complex sentence: Gilly is horrified to find himself engaged and tries to act like a slob to put Cherly off of marrying him however this doesn't work however when Gilly accuses her of having an affair with Rhys Ashworth to which she dumps him.
Split into simpler sentences: Gilly is horrified to find himself engaged and tries to act like a slob to put Cheryl off of marrying him. When Gilly accuses her of having an affair with Rhys Ashworth, she dumps him.