AliceAnne, I am aged 77 and thankfully still fully fit and still engaged in the business my wife and I began in 2003. That stated, the behaviour your husband is exhibiting, I can assure you is not normal for males of our age.
I have a brother aged 79 who is disabled by way of Parkinson's disease and is exhibiting very similar behaviour to that which you describe. In his case, it was found that he has been in extensive contact with women on dating sites. His own wife has been deceased for several years, but his cleaner who also acts as his carer was the person to inform his three sons, and myself of the problem.
We all agreed to contact the local social services and we all now acknowledge they have been wonderfull. They had an NHS medical consultant go to his home and it was diagnosed that he had the early onset of what is known as " Parkinson's dementia".
They have now set up his computer, tablets and phone so that he can no longer be used to make him vulnerable to anyone carrying out abuse of him through those dating sites, and his eldest son now has power of attorney over his estate.
AliceAnne, I believe that your husband may well be exhibiting similar mental decline that my brother was displaying in the autumn of last year. In that case, similar action to that which was taken on my brother's behalf could well benefit both him and yourself as you also need protection in this situation.
Please do not take any notice of the usual members of this forum who always use any "cry for help" in these treads as an excuse to tell persons to break with their partners. This is, I feel, mental illness coming to the fore in your husband, but help is available for what is without a doubt a very distressing time for yourself.
I am on a break in the office at the moment but thinking of you by way of the situation you are in, and hope this helps