Family Issues

I need help. I have been with my SO for about a year and a half. He has met my kids from a previous relationship and also has met pretty much all the important people in my family but I have yet to meet his daughter from a previous relationship or any of his family. Anytime I ask him about it he says if we are going to be together it is bound to happen. It makes me feel like a secret and out of the loop. HELP. I'm not sure if I'm being over dramatic but it definitely hurts me.