J.R.
My son didn't see his Bio dad until he was three and has only seen him twice since then. I told him that Daddy X loves him very much, but that he can't come see him right now even though he wants to very much. As he gets older he'll realize that it's his dad's choice but as for now that's what I tell him. I plan to explain later that his dad wasn't grown up enough to be a daddy so he picked his new daddy for him.