Oh, Una! I have been in the same situation twice in these past two years, and my heart goes out to you.
Take comfort in knowing that the decision you have made is the kindest, most caring thing for Riley. If he could speak, he would tell you how much he hurts, how weary he is. He has lived a long, loving and love-filled life. You are now offering Riley the ultimate act of selflessness - the release from suffering, even knowing you will grieve.
It’s a difficult hurdle, but once passed I believe that you will feel a certain peace settle in your soul, knowing you did the right thing. If possible, have the vet come to your home, so that Riley will be in familiar surroundings as you say good-bye.
I believe in the Rainbow Bridge, “just this side of heaven” - beyond which is a golden place where all of our beloved pets run and play, sound and strong and free of pain. I believe they wait for us there - I believe we will be with them again.
Until then, cradle Riley in your arms - he will feel the love - and then release him and let him fly.
My thoughts are with you and your family.