Despite no having a romantic relationship with Alison, he's always there to help her during times of need. He later works for a newspaper, and later starts working at D&D Advertising with Alison and Amanda. In season one, he dates Amanda briefly and she becomes pregnant with his child, but soon miscarriages. He and Alison get engaged in season two, but she gets cold feet on the day of the wedding due to personal issues with her father.When Kimberly Shaw blows up the apartment complex in the season four premiere, Alison becomes blind temporarily.
His marriage to Brooke puts a strain on his friendship with Alison.
After Brooke's death, Billy became very angry and hostile towards others.
She immediately took an interest in Billy, and since she did not want others in the group in the way of her relationships, cut them out of the picture, and convinced her father to arrange a marriage with him, and made Billy believe that she wanted him.
During this time, Brooke and Billy become engaged, but she appears to have been in an affair.
At the end of the series, Peter and Amanda became rich and moved to an island, escaping the country to avoid jail time.