So first, let me talk about your wife. It may help how you view everything.
Your wife doesn't actually have "problems" - many women are unable to orgasm without manual stimulation. This is just how she's built, so to speak. Since she knows exactly what gives her an orgasm, have you asked her to show you how to do it so you can give her an orgasm? Instead of her taking over, have her help you. Tell her you want to connect with her in this way.
And she does need you. Even if she doesn't "need" you to orgasm, she "needs" you in so many other ways - as a friend, a partner, a companion, etc. You seem to be putting a lot of focus on the orgasm, and I understand why, but I'd bet she isn't. There's so much more to you and your relationship than the orgasm.
So with your ED, I don't know if you're a good candidate for Cialis, but maybe that would help you more than Viagra. Maybe not. Talk to your doctor.
So what happens if nothing ever improves? Can you find peace with it? Are there other ways you and your wife can connect physically and intimately without the orgasm, for both of you, being the ultimate goal?
For example, some find oral sex is really intimate, and even if it doesn't end in orgasm, the connection may be enough. She may not have a lot of sensation in her breasts, but it still may feel erotic when you touch them.
Maybe if you shift your goal from the orgasm to connection, you'll feel less frustrated.
And remember that even if you never give your wife another orgasm again, she needs you. You are so much more to her than that. I'd bet that you are placing far more weight on this one thing than she is.