Earplugs or a very good noise canceling headset - Or a new girlfriend…

Too bad she's that unconcerned about her health. I don't think forcing an ultimatum is a good idea if you're truly in it for the long haul, but try talking to her again. When my dad was diagnosed with sleep apnea, ho was told he worked harder trying to get one night's sleep than he did his 40 hour factory job. Have you noticed if she ever stops breathing when she's sleeping?

Tell her the hardships you're going through. Tell her it's impossible to sleep there as her snoring is keeping you awake, that you can't even sleep on the couch because her snoring is so loud, and that you're worried about the long term effects on her health. Ask her to see a doctor for treatment; if she refuses, you don't sleep over anymore/get your own place until she does. If she still won't, you're better off without someone with that level of selfishness and disregard for personal health and the physical toll it will have on you.

sleep apnea is very serious it will give you enlarged heart valves that leak.

Snoring often means she has a breathing problem like sleep apnea. Chances are she's getting really low quality sleep if she's that bad.

honestly you should invest in an adjustable base to go under your mattress, lift the head 3-4 inches at night

Snoring like mad throughout the night can be a symptom of mild sleep apnea, I believe. While sleep apnea is generally not life-threatening, it can easily cause the quality of your sleep to be less than adequate, which in turn can lead to slightly lower cognitive function, or at least mental stress over time. This occurs due to your body fighting to get the air it needs throughout the night. People with moderate-severe sleep apnea may even "wake up" multiple times throughout the night as their tongue covers their throat and they lose the ability to breathe until their body wakes up enough to cough it out of the covering of their throats. Most any small change you can make to improve the quality of your sleep is a change you should make, including a trip to the doctor's. Disclaimer: Not a doctor, but have had loads of medical classes towards nursing, and have improved my own sleep with great effect. Hopefully this was at least interesting, have a good one!

She probably has sleep apnea, tell her to go to sleep clinic and get a CPAP machine; it will stop her from snoring, sure you will have to listen to the machine at night but it's not as bad as the snoring and tell her it can be life threatening and you want to spend as much time with her as possible