Very sorry to read this.
Having just gone through the same I can feel your pain. The thing is that all dogs want to do is give to you and the greatest thing you can do when it is time as hard as the decision was, is prevent them from suffering.
I wish you and your wife all the best. Focus on great memories of things you did together and talk about them. I made a screen saver camera roll that includes pictures of all the dogs we have had. For me recalling the good memories has helped.
