I'm having a pretty big issue here, it's been a fucking long time and it hasn't really been resolved. I guess I just didn't have the energy to deal with it but it's reaching the boiling point. Basically, my parents and my sister do not seem to welcome my girlfriend at all. My sister's always been weird, she just hides in her room if there's a guest over. My girlfriend isn't just a 'guest' though, and each time my gf comes over she just walks away and doesn't even try to say hi. My girlfriend is really upset that my sister does this, and also because my family does not invite her to any of our activities. My family does not do that much at all though, so mostly just a dinner a few times a year if anything.
I'm sorry, I'm not quite following you here. I understand your sister is acting like a bitch, but how about your parents? You said they don't invite your GF, but they invite you, right? They don't say "don't bring your GF with you" do they? From your post it doesn't seem to me they're doing anything wrong, but of course there could be some other things you didn't mention in your post, so sorry if I misunderstood.