Complex sentence: Jeff breaks up with Hayley, causing her to go on a destructive rampage that has happened every time a boyfriend broke up with her and leading her in the arms of Stan's CIA body double, Bill from It's Good to Be Queen.
Split into simpler sentences: Jeff breaks up with Hayley, causing her to go on a destructive rampage that has happened every time a boyfriend broke up with her. However, it isn't Stan--it's Stan's CIA body double, Bill from It's Good to Be Queen.