What to do when you have all but the rarest stamps

Jonty wrote: I wasn't going to mention any names, That "A level" guilt you have will be your undoing!

Charles, I am reminded of parallel situation to yours via a charecter in the British Comedy series Psychoville. You may not have this broadcast in Thailand but if you do do not miss it. In a way it is both similar and different to a reply on this subject you got elsewhere.
Basically the character, Oscar Lomax, is a blind wealthy recluse who obsessively collects little stuffed toys. He nearly has the set. They are kept in an air-conditioned locked safe room; the Holy of Holies. He just needs one more though - Snappy the Crocodile. They are rarer than you-know-what. And then suddenly it pops up on eBay. A bidding war starts with Lomax competing with a pair of conjoined twins in Essex. We watch the bidding climb from 99p to thousands of pounds. The seller realising something is odd, and realising that that can't actually put their hands on the toy, withdraw the sale. But after some double dealing, subterfuge and bribery Lomax finally gets his hands on Snappy.
He actually owned Snappy once before. He knew it was the same one from its smell. The twins had beaten him on eBay that time, but had exchanged it for Lomax's eyes, hence his blindness. He reveals that during a spell in a mental hospital he let it be stolen so that he could once again devote his life to tracking Snappy down. Now he owns it again he immediately throws it off a cliff into the sea.
Lomax suffers from Paradise Syndrome. He can only be happy if he wants something virtually unobtainable more than anything else in the world. Significantly, he refers to his collection of stuffed toys, not as a collection, but as 'commodities'.
I am not suggesting you have Paradise Syndrome nor that you act likewise.
Incidentaly, I thought I saw Snappy in a toyshop window last year, and nearly bought it. Then I realised it was the wrong colour.