Ignore for now. Should subject be revisited smile nicely and say, "IF he is EVER for sale I will be sure to let you know".
You sound like a great partnership. Long may it continue
Some years ago we had a similar experience. Bought from a friend of a friend. (Turned out to be unregistered dealer). Had him for 3 weeks at a livery yard. We had not long left for lunch when apparently they drove into yard, told only person there we had sold them the horse. Bought him in from...
You don't click. So she may well be the perfect horse lifelong friend for the next owner.
It's never easy parting with an animal and its natural to want it gone quickly.
when you find the right home for her you will be able to relax and move on. It's always a difficult time