[Legate of Amon Lanc]

Well, the point is, he was not bound to the Ring in any "metaphysical" way like the Nazgul were, in the simple language, he was not held together by a spell. He would not suddenly die, the same way as Bilbo did not suddenly die - it's not that now all these years he gained would disappear upon destroying the Ring. But he would perhaps be close to die of old age, yes, like I said above. Mainly, because there will be no will for him now to keep living: no hunt for the Preciouss, which was the main "motor" for him to drive him to live. Perhaps he could find a new meaning of his life after this, if somebody (Frodo, Gandalf...) helped him to find one. And he would certainly not have any active "job", truly. He would rather dwell somewhere in retirement, much like Bilbo in Rivendell, and eventually do some simple things to pass his time, often probably just walking around in the nature, or fishing. But even the gardening is not that far - I mean, Sméagol liked to "dig in the ground" (perhaps he will eat some nice wormses while gardening. And the rest he will put in his bait bucket).

But as for the second part of your post, you are being too pessimistic, Bb. I think he would be able to cope - but only under the condition that he would be able to put away the thought of possessing it willingly. Like Bilbo, who passed the Ring to Frodo willingly. That was the important thing here, and here it would pass on to the psychological level.