My SO keeps me out of his son's life but expects me to cook dinner and talk to son when he is here for the week.  He tells me nothing about how his son is doing in school, appointments he has with the counselor, health issues, and all family goes to school events except for me.  When going back to mother's, SO will have his son give hugs and say goodbye to everyone in the family except me.  When son is here for the week, going to bed at night, the two of them say goodnight and totally ignore me.  (Side note - SO and I live together so this is my home too).