It's really your call as nothing we say can make up your mind. You are the one living the 'nightmare.
Lots of sound advice but one thing to remember. The decision you make might alter the rest of your life, for better or worse and there will be no going back on that decision as it would be thrown back in your face every time you argued.
Your home isn't a hotel and you need to ensure that your OH/DH understands that his son laughing at you is, in fact, belittling you, saying that what you ask if him is of no consideration...in other words, 'stuff you'.
Perhaps you could stay with your family for 2 weeks after telling your husband that you need a break or plan 2 weeks away with him.
When you return, the state of the house will tell you what you need to do next but in any case, plan carefully. You don't say if you work, what your finances are, who owns the house, whether you have your own car, whether your husband works or if the son pays his way.
Meantime, stop cooking his meals, stop clearing any mess he leaves in the rest of the house including the bathroom and make no excuses for your views on his slobby son.
While you keep on doing what you're doing, nothing will never alter.
I wish you luck and strength to make a choice that suits you. 
