so everyone on here would ASSUME and NOT ask??? is that correct?
I don't understand why you are getting so heated over this... Yes i would assume my partner and DD were invited if i got an invitation for a birthday party. If a friend turned around and said no it was just me who was invited then i would decline the invitation and more than likely not speak to them again.

I had people at my DD's birthday party who's kid/s had never met my DD before but thats how kids get to know each other...