I agree with AnnieBrooke about having your husband get a check-up. My husband snored loudly for a year before his heart attack. Otherwise he was healthy, no high blood pressure, etc.
My friend's husband snored like a bear until he got a special mouth guard from his dentist. It slips in like a retainer.
Wear out your son with swimming or a marathon bike ride on the day you put him to sleep in his own room. Buy him a new comforter now that he's older, and though it will be tiring, keep putting him back to bed when he comes to the living room.
Good luck. :)
Gee whiz, the first thing to think about fixing is your husband's snoring. If it's that bad, he might well have sleep apnea, which is terrible for his heart. Has he ever talked to a doctor about it?
If that can be fixed, you can move back into your own bedroom. Or get sound-blocking earmuffs of the kind they sell at equipment dealers and just go back to your bed whether your husband is snoring like a chainsaw or not.
I assume your concern is keeping your son from being in the habit of sleeping with a parent, not so much as keeping him out of the living room per se? If you get yourself back into your own bed, your son might just go back to his own room and his own bed. Or he might sleep alone in the living room, but at least you won't have to fight about keeping him in his room and away from you in the living room.