Take into account his life is also turned upside down. My stepdad also had a hard time watching me having excited chats with my absentee dad while technically, he did all the dad duties. Though he never acted jealous or pissy about it. But please take into account if he's been around for long then this is her life and her parents. He is not some kind of 'fake' just for not being the seed that created her. In a way he is her dad too, and more than you have been, even if it wasn't in your power. It's not odd if he's protective and I think you're going to get further if you understand that & talk than if you go into it like a battle with an insecure rival