Complex sentence: Phil and Jay leave Frank alone there since he found a woman to flirt with, only that on his way home he meets another woman, Jeannie (Peri Gilpin), who he brings home with him.
Split into simpler sentences: Phil and Jay leave Frank there alone, since he found a woman to flirt with. On his way home though, he meets another woman, Jeannie (Peri Gilpin), who he brings home with him.