Rather drastically, tell him if he doesn't want to do this for himself, or for you, then he needs to get you a good life insurance policy on himself, for you, cause you're gonna need it!
Now, this may sound harsh, but sleep apnea is nothing to play around with, and if he doesn't get it treated, then he's gonna eventually die prematurely from it!
Calmly re-inform him that there are many options for treatment out there, but most us us would agree thet the xPAP is the best form, due to its' adjustment under monitored conditions. In other words, they can prove it is working. However, some people can't adjust to using the xPAPs, in which ever form you need. But with many options for masks/nasal pillows, etc., there is bound to be a method that should work for him.
Also, keep on loving him, and remind him to address this with an open mind about it. From my encounters, I think that is the one reason I did not need an adjustment time for mine. I WANTED IT!! I went for it! I got it, and I've had it for over 12 years. The only times I don't use mine at night is when there is no power and it won't run, or when I'm up doing surgery at night. Either way I'm not sleeping at those times.
Bottom line for you, though, is to keep loving him, and ENCOURAGING him, WITHOUT NAGGING him, and eventually he should come around to it. You might also check with the sleep lab to see if they have a local chapter of A.W.A.K.E., or some form of support group. Get him to go, or you go without him. Maybe they can offer some help.
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painless
Sleep Apnea is a Killer! Get it Tested!
Get it Treated! Use the Treatment!