I knew a couple like this, the husband would moan about things he couldn't change. Every time he started his wife left the room, he eventually got the message and stopped moaning.
Yes, fruitsalad, it certainly can have a very negative effect on your mental health. I have been so close to leaving on a couple of occasions.
The situation here is complicated by Asperger Syndrome.
I can’t advise you but I truly sympathise. Do you have a close friend to talk with? That helps me.
Probably a downer. But they may well have reasons to be grumpy and miserable. Why should you want to make it worse for them ? Find solutions not escalations.
Talk, talk, and then talk some more.
Tell him how you feel, he probably doesn’t even realise how grumpy he is, or how down you feel about it.
Unless you’re honest with him, he’ll never know.
Failing that, go out, join clubs or things, go shopping, go to the cinema, visit friends, let him stew in his own miserableness and get yourself a life where it has no impact on you.
Good luck.
Is he working fruitsalad? If not, it may be that he has lost his sense of purpose and this is a signal of mild depression. If he is working, he sounds pretty unhappy with his lot and probably needs a change.
Could you encourage a change? or help him to accidently on purpose stumble upon a volunteering opportunity? He might be more cheerful if he were involved in some new activities and mising with others.