hey flurint, tough situation you are facing. i feel for you. i am not against arrange marriages if both individuals are happy with it and are given time to like/dislike each other. personally i woldn't want to be arrange married. i know a girl at work whose family is actively seeking a partner for her, and she is scared and doesn't want to go down that road. she is under a lot of pressure and is far too scared to stand up for herself.
so take a minute and think about the situation your gf is in. given that you only love her a 70% (and i thought love was blind!) and are not ready to marry her or whatever, that is not the point. the point is that she is facing an issue at home, so be the support she needs and help her work through it. help her stand up to her family. look, i can understand that you are angry at a lot of people and moreso traditions, but what your gf may need right now is simply a friend, to stick around through thick and thin, not a life partner. she already has that on offer.

i hope it works out for the both of you. It will.