Welcome to the forum. My partner is 60 today and has probably had the disease for about 4 years. One of the first things I noticed was his change in personality, but rather the reverse to your partner. Mine has become very introspective and hardly talks at all. He rarely starts a conversation now and answers in momosyllables, this from a man who when I met him was the organiser of a singles social group and had to meet and greet people he had never met before and arrange and organise activities for a whole group of diverse people.
It's very sad. He also has no conception of how this affects me, and no interest in our relationship or how I am feeling. I have moved permanently into the spare room! I no longer feel that I am anything but n unpaid housekeeper and carer!
It takes away the person you met entirely. That is very difficult for everyone that it affects, but maybe if you have been together a long time and have children together and other memories, you have some "glue" to keep you going. If however, like us neither of us have children and have only been togather 8 years, there's not a lot to keep you together as a unit.
However, I digress. Just to say you are not alone a change in personality is quite usual, and maybe (who knows) ? the personality may change again?
This forum is absolutely brilliant for all sorts of reasons. It puts you in touch with others in similar situations, it is a wealth of advice and information, it makes you realise you are not alone, it's never judgmental, it gives you somewhere where you can "sound off" about things without any comeback (as long as it's not abusive, racial or discriminatory in any way) and you make "virtual" friends.
I don't visit often enough, but keep with it, and if you ever need help, advice or friendship, you know where to come......here!