Humans spend about a third of their life a sleep. This has the potential to become a big problem, but it can be fixed with devices like breathe right strips. I'm sure it would affect your relationship if you weren't getting enough sleep, which leaves to cranky behavior and over-all not being on your game. Even if you opt not to sleep in the same beds, the lack of intimacy of sleeping in the same bed could lead to other problems in the realm of intimacy. If you can't take it, propose that she gets some help and ask her docter about options. ( there actually might be surgeries availible if you wanna go that far.) For now she's just your girlfriend, so if this is a hypthetically problem where you actually are not affected by her snoring, dont let it determine where your relationship leads.