I suffered years of unreasonable behavour, verbal abuse, mood swings before my husband was diagnosed with this awful disease. Now PSP has took hold , mentally he seems alot more chilled than he has been. His sexual appetite does appear to have reappeared and like you I have no desire to have sex plus he has ED so its not really possible. However the years of bring treated bad have destroyed any sexual urges on my part and even his touch is not the same since this disease has took hold. I care about him and will care for him but I have no desire to have sex or any sexual interaction. It's difficult so I either pretend I'm asleep or go to bed later than him to avoid the issue and I still work so I'm up before he wakes.
I do understand how difficult this is and the frustrations and stress the caregivers go through. I joined a gym about a month ago and it's the best thing I've done. I feel mentally and physically better and stronger mentally so its helping me so much in dealing with this awful disease.