Sure I can understand what you are saying. But you could always approach him with options of what you would be good with too. I mean, hey there's oral, there are toys he can use on you. Sometimes people forget that sex doesn't just have to be one thing.....there are many options open.
You might even just approach him with something like this...and I'm sure others will chime in here. That you'd find it a really loving gesture for him to just take care of every now and then. Hey...he listened about the other things didn't he? He may have ED....but you can still approach him with things that YOU would like, that he CAN do....but ya know, you'd just so much prefer it if he did it for you, instead of you doing it for yourself