ED/Low Interest in sex

I am in my mid 50's and my GF is 60. We've been together for about 16 years. When we first got together we had a decent sex life with normal relations but due to multiple factors it is now almost non-existent.

The first of the factors is that we both work for the same company and it wasn't widely known for many years(still not openly) that we were together. When we were in public she would not allow any signs of affection for fear that someone in our industry might see us (we work in a broad industry).
This even included when we went on vacation to places with very few people. This put a strain on my feelings for her as I wasn't able to openly hold hands, hug or kiss her.
When she hit menopause things got worse. When I would come on to her at home she would push me away often with angry statements like " leave me the F alone" and "when will you learn I'm not interested in that anymore" It literally caused me to fall out of love with her. This ebbed one night when we were asleep in bed. I was dreaming in what you would call lucid dreaming. In the dream we were making love, while asleep I acted out the dream by placing my arm around her and moving close to her. She woke up elbowed me hard then turned over and hit me and yelled for me to get away. I was still not fully awake and moved away. In the morning when I woke up I honestly wasn't sure if I had dreamed it or not until she came into the bedroom and said I better not try that again and stating it was like I was trying to rape her in her sleep. At that point I completely gave up on any physical relations with her and took my frustrations out with porn.

To add to this she often made statements about me having online GF's and even having sex with others when I traveled without her, which I didn't. In my former marriage I had several affairs including her and didn't want to repeat that so I buried my desires, sort of a mental castration.

Now today with menopause behind her she wants sex but I can't get it up for her. She wants oral from me but refuses to give it to me. She wants massages and otherthings but again it's only one way. I have started on Viagra which does help a little but I think the real problem is in my head and I can't seem to get past it. I love her and she does love me, but I don't know how to forget the past and move on. It doesn't help I have a photographic memory and replay the scenes. Not only can I not get it up for her, I'm no longer interest in women sexually. I appreciate a beautiful woman but there is nothing going on as far as libido, I have literally had half naked show girls dancing around me and nothing, not even a tingle. Same thing when I have had an attractive woman come on to me.
I don't know what to do anymore, how to "forget" the past, how to re-stimulate my libido. I'm decently built and in fairly good shape and health and it's so frustrating that I no longer have a really sex life anymore.

I went through a similar situation. You go through different stages in life. There are periods where you go through physical changes and mental phases. For either reason men and women can lose their libido. The desire , the passion , the physical ability to want and have sex is just not there.
You have a lot to unpack in your post. The bottom line , IMHO ,
is both of you are going through severe physical and mental changes. I think both of you would benefit from individual and then couples counseling with someone who can help you better understand what's happening in your head and body.