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Forget the past about it all, because it only makes you disappointed. You sell Bitcoin from savings to treat your sick wife and save your wife. That's something commendable. This Bitcoin is worth nothing compared to your wife. What you have to do now is try to get back to getting Bitcoin even though it is not comparable to what you got in the past. I am touched to hear your story and your struggle.
You're right, maybe the OP will regret it more when he prefers to keep his bitcoins. What you do is right even if you lose bitcoins but you still have something more valuable than that. After all, saving someone would be more important than anything else. If I were in the OP's position I would do the same thing as the OP did.
Just imagine if you don't do it for your wife, maybe you will regret it from now on and maybe you can't forgive yourself.
Maybe I will say, do not regret because something you do is more valuable than anything.