If I put myself into your place, I would probably feel rejection? Is that how you might be taking it? Understandable, and I don't think you're being selfish. If you were really selfish, you would just leave him without any chance to get some help for his ED. But, beings you want to stick with him and work this out, as you say, there is more depth to your relationship than sex.
I am wondering what feels more like a betrayal to you? His addiction, or his ED? Both, perhaps?
Personally, I don't believe in 'fairy tale' romances/relationships. I don't think that's pessimism; I think it's reality. There most always something going on with people and between people that make so it's not a fairy tale, but facing what you're really dealing with and deciding what you'll do to resolve it. To some people, this may not seem very hard, while to others it's a difficult task that takes lots of work. I guess it depends on your experience. And, maybe it also depends on whether or not you think it can be resolved or whether or not there is a viable answer.