I sympathize with you. This is a terribly painful situation. Unfortunately, there are no good alternatives.

Obviously, I can't speak for your husband, but if it were me, I would want to depart this world peacefully and with as little trauma to my loved ones as possible. The thought that I was causing them agonizing decision after agonizing decision would upset me terribly.

That being said, if the roles were reversed, what would you want your husband to do for you? That may not provide the answer, but it's a place to start.

Whatever you decide, do not second-guess yourself later. You are clearly a loving woman who wants what's best for your husband. That will be your best guide.