Dominick's current girlfriend, Joy, is probably the most joyless character in the novel, but she sure has a positive outlook on life.
Joy and Dominick have little in common. They met at the gym where Joy works. There's a fifteen-year age gap between them, though, and Joy is afraid of Thomas. Plus, Dominick calls Joy's best friend, Thad, "the Duchess," and not in a Fergie way, but in a homophobic way. Here's how Dominick describes his relationship with Joy: "Joy and me: we were like two people trying to communicate from opposite rims of the Grand Canyon" (7.81). Ah, romance.
Joy had a joyless upbringing. She was sexually abused by her uncle, and she still has an unresolved attraction to him. She's been married twice, and copes with stress by shopping and shoplifting—and when she thinks about shoplifting, she touches herself. Really.
When Joy gets pregnant, she lies to Dominick and says it's his baby. He knows it's not, though, because of that pesky vasectomy that ruined his first marriage. Joy admits that it's Thad's baby. He's not gay; he's bisexual—oh, and he's her uncle. There are more twists to this story than a season finale of The Good Wife.
Joy ends up showing Dominick the baby, Tyffanie Rose, and then she dies—Joy, not the baby. Dominick adopts the baby and lives happily ever after because, once again, it's all about Dominick. He doesn't seem upset that Joy dies at all. Dominick probably thinks her death, like Thomas's, is a mercy, even though Joy was one of the only people who tried to get Dominick to take care of himself instead of devoting his life to Thomas.