Hi Dan:
I am a relatively new collector, so my personal experience is perhaps not terribly relevant to your situation, though I have thought, at some point, I will have to part with the cards of which I'm become so fond, and I know that will be a challenging decision.
Just yesterday, I watched a Ted talk from a scientist/author named Dan Gilbert on the subject of happiness. One of his basic arguments is that, as humans, when we part with things we like, or when bad things happen (i.e. like break-ups), the disappointment tends to erode faster than we initially think it will. This is because we tend to overestimate the impact of future events, good or bad. I'm oversimplifying, of course, but it was a very interesting discussion nonetheless. It may or may not be of any relevance, but if anyone has a spare 20 minutes (never a given in this hectic world), it's not a bad use of time.
Cheers, and best of luck to you.
https://www.ted.com/talks/dan_gilber...py?language=en