I've only just learnt the full story

This happened many years ago, but I've only just learnt the full story.
I had a dysfunctional childhood and as I grew into adulthood, realised I needed male attention. I was ok during all of my marriage, 30 years at that time, but then I hit the menopause, felt like I was past my use by date, no longer attractive to the opposite sex, no hope of that career I'd always craved.
But, I had a computer and although I didn't deliberately set out to cheat, it happened. My husband found out. I ended it all, but honestly can't remember if we had a discussion about it. I hope I apologised and told him it was all over. We really should have seen a marriage counsellor, but that didn't happen either. Looking back now, there were red flags after that that suggested he was using a prostitute, but I was too naive and trusting to query my husband. This all happened around 2003/4. I decided to go back to work, which would have given my husband ample opportunity to cheat. I stopped working in 2010 and everything seemed ok between us except I could no longer have sex due to pain issues with the menopause.
My husband has recently been admitted to secure dementia care and going through his bits and pieces I discovered that he was still checking up on me in 2014. I used to have a perverse pleasure in creating fake email accounts. I did this for various forums I was in, all perfectly above board, but he had copied them all down, plus a man's name I had jotted down. In amongst it all was a phone number for a sex worker (obvious from the name). He used to save the money I gave him each week and I could never understand how he was spending it as he didn't smoke, drink or play sport and he would sometimes tell me he was short of money. The only time his savings accrued at all was after he lost his driver's licence at 80. I am 10 years younger than he.
I blame myself for the years of intimacy we have lost, 10 years and for the sequence of events. I am so stressed out to think he was having physical sex with another woman and I now cannot have the conversation I need to have with him. There is no closure. Perhaps worse, is that I have npw discovered if I use a tiny amount of hormone cream, I would be able to be intimate again, but it's all too late, there's no closure and I am so bereft, can't forgive myself for the mistakes I made and what I've lost. He has probably forgotten what happened (I hope) but does tell me he loves me when I visit and I also tell him the same. I love him to pieces, but the memories I now carry are all painful ones and I don't know how to get over this. I am an emotional wreck and my pulse rate is sky high. I've seem my GP but he says it's not high enough to worry about. It's mostly over 100.
Can anybody help me to forgive myself and let this tension and anxiety go? Thank you.