DP has sleep apnoea, DS and I are both autistic, DS being quite high needs and rarely sleeps through the night, and we briefly tried a stint at living together which did not work because of his snoring. He also has a CPAP, worth trying different sorts of masks and fittings to see which is comfortable, but even with the CPAP DP could still snore so loud it could be picked up on the richter scale.
He saw 2 ENTs, the first said he had a mild deviated septum, not worth operating on, gave him some flonase spray to try and reduce inflammation.
That didn't work, so he went back and the 2nd ENT said he did have a mildly deviated septum, but enlarged turbinates and adenoids and needed surgery on all 3.
The waiting list was long, but he finally had the surgery this year, and still has a mild snore, but it is within a normal range, and the resumption of the CPAP has now made a world of difference.
We still live completely separately which is understandably and presumably not an option for you.
However, for a long time DP did not understand how his inaction on seeking a diagnosis or resolution was negatively impacting our relationship and that inaction almost caused the end of us, because not only is sleep deprivation torture, it's an utter lack of respect towards the caring responsibilities I have for my child (also on a part time schedule at school), which impacts my ability to cope, function, and support DS with any therapies or catch up academics we can do at home. It was a clear case of it's me and DS vs. Him and only he had the power to change that to me and DS AND him.
You need to consider whether you're willing to let this be the rest of your life. You can't change your caring responsibilities but you can accept that if someone is not willing to be part of the solution then they are part of the problem and you can choose to endure it or let them go.