Complex sentence: Shortly after, Lois returns home furious and, after Stewie kicks and punches her for yelling at Peter, demands Stewie go to his room; when Peter fails to back him up and disagree with Lois, Stewie feels betrayed.
Split into simpler sentences: Shortly after, Lois returns home furious and, after Stewie kicks and punches her for yelling at Peter, she demands Stewie go to his room. When Peter fails to back him up and stand up to Lois, Stewie feels betrayed.