I'm so sorry.
It is such a difficult decision, but it sounds like you've really thought it through.
It's always the right decision when it's well though out, as well as based on what you feel in your heart is best for him.
It's human nature to doubt such a terribly important decision.
I can't imagine how hard it must be with such a magnificent creature.
As I said, it sure sounds like you have his best interest at heart,
and that's all that matters, in the end.