She left in 2015, but hadn't been sexually involved with Rafe quite awhile before that. She went to say goodbye to him and they had a farewell dance at Edge of the Square (Victor's club that Rafe was managing) on her last day.
Obviously the writers can rewrite history (look at Paul being John's son when there is absolutely no way it could've happened by what we saw on-screen), so I guess we'll see if this is little David Hernandez or if he belongs to some random man she hooked up with. Although, heck, for all we know, she could've kidnapped him from someone.