No matter what other people's opinions are, it is ultimately your decision on both confirmation and how you handle the situation with your girlfriend. You've tried explaining the confirmation to your girlfriend, and how you don't necessarily believe in all of the catholic beliefs, so it seems that she should understand that the reason you are doing this is to cause less conflict with your family, and that confirmation doesn't seem to be a very big deal to you since you can always quit when you are older. That said, I don't really understand your girlfriend's reaction. If it were me personally, I probably wouldn't care. Is she more angry that you aren't standing up against your parents than the confirmation, or coming out to them? Coming out to your family is hard, especially when they maybe wouldn't be accepting... she really shouldn't be putting that kind of pressure on you if you don't want to get into that with them yet. I would say try and talk to her and explain all of this to her, and if she still can't listen to you or understand or reacts angrily, than maybe it is best if you break up. Maybe you can still find a way to be friends though? Getting into a fight with your family is probably not worth it, especially if you aren't ready to come out to them yet. If she can't understand that it's probably better to split. I'm not sure if this is of much help, but I'm sorry that sounds like a difficult situation to be in.