I do sympathise deeply with your situation.
Love is about individuals, but individuals are connected with a series of deep and complicated threads, each different for each person.
I fully understand that because you love your GF so much, you want the world to know, and are hurt that she appears not to feel the same way.
However, as an outsider, I can see that there are a number of complex issues at work here - the relationship acceptances in families that occur with all couples, strtaight or gay, are various and complicated, so try not to feel as though it purely your same-sex relationship that affects your GF's approach to her family and the wider world.
My mum was hostile to my girlfriend (now wife) becuase he was divorcing and had two children when we met - she was not deemed 'suitable', and I shouldn;t be raising 'another man's children'. Yes it all a bit 1950's, but generations, and attitudes to vary a lot.
I think Pickle'as advice is as always, measured, caring, and base on experience, and he is right that you should not push the issues because your 'victory' may be Phyrric if it makes your GF unhappy.
Try a different tack - revel in the fact that no-one except a very small number of people know of your love and happiness together - it can be your secret unknown to the world, special and private.
In an ideal world, you could be 'out' with no complications, but that;s not where we all live, and as i said, compromises have to be made.
I am sure your love will survive the additional pressures put on it by our stiraht-based society - just make sujre the wider world and its impossible-to-please scenario doesn;t enter the world behind your front door, which is just the two of you - as it should be.
Your partner is a lucky girl - butIam sure she knows that.