 After Debra finds out that her father cheated on her mother with a CI, she becomes wary of Anton and they eventually break up.At the end of Season 3, they get back together when Debra realizes (with the help of Dexter) that her father Harry would have been so proud of her for being a great cop and getting her detective shield, regardless of her relationship with Anton.At the start of Season 4, their relationship starts to move forward just as Lundy returns and admits he still has feelings for Debra.