Hello KoKo,
First, I am so sorry that you and your partner have reason to come here.
While I am not gay, I too have had someone I love hit by dementia. I can imagine how you feel. You were smarter than me though, I waited 3 years (going it alone) until I visited the forum.
As others have already pointed out there is a strand here especially for gay people. However dementia knows no boundaries - my mother was intellectually gifted and it is gnawing at her brain, it robs young and old alike of independent life, and unlike Western society, dementia treats gay people the same as straight, real equality! Oh, I made a mistake, I think dementia prefers females over males, so there is gender inequality!
Sexual orientation aside, I think you will find some seriously experienced people here on the forum. I joined about 2 months ago and it has helped me to face what is. I was in denial, now I am not. I have grieved and cried and cried, and kind, knowing people have gently guided me along. I have signed Mum up for a care home, and again people here have shown me the route already travelled by so many. I act out and they catch me when I fall. This is a wholesome place and I am glad you have found it.
I look forward to hearing more from you. Whatever your state of mind, someone here knows how to support you. Best wishes, BE