My partner has told me he wants to be a woman
I am in hell at the moment my partner of 26 years has recently told me he wants to be a woman all I feel is Despair my heart I feel has literally broke in two
You're not alone if that makes you feel any better. A woman told me not to long ago that she could relate to a man wanting a gender change. A woman trapped in a man's body. You have to convince him that there can be a lot of problems with a gender change. Forever taking hormones, there's no turning back. There's someone that wishes she had never done it. No one's attracted to her as a woman. Plus you have to go through a transition period where you dress and behave like a woman before the procedure. I'm guessing you already knew that.
Before he decides have him read about the potential problems with transgender assignment. Google it.
Have YOU been in denial about where this was all going?
Surely, you must have had clues (The entire Jenner family knew about Bruce's behavior long before he came out publically - even the ex wives.)
There are groups that offer support for families of people who transgender. Get some help with this.