Because Will didn't need him. He learned how to fight without him. He got through his first date without him. He learned how to play ball without him, and he got pretty good, didn't he? He had FOURTEEN great birthdays without him. He's gonna graduate college without him, he's gonna get a great job, marry him a fine honey, and have a bunch of kids, and he definately don't need him for that cause there ain't NOTHIN he can teach Will about how to love his kids! TO HELL WITH HIM!