After 30 years...why now?

Yes I agree with Blannie. Outside help so you have a chance to remember yourself. You are still quite young and you are dealing with a lot. I too married an older man and now he has Alzheimer's. I once was his darling and now I am his mean mom.
I think we mourn what "used to be" and still want them to behave the same way toward us.
My husband and I have been married 26 years.

If he has a brain shrinking disease, it may be a part of the disease. I wouldn't place too much emphasis on it. I know it's hard to care for someone you love and to watch them go downhill. But don't torture yourself by focusing on what he calls you. I'm sure it's hard for him too, having you become more of his caregiver than a wife. But neither of you can help that situation...

Is there a way you can get some outside help, so that once in a while you could share some time as a couple, maybe a meal together with candles and music, or something that you enjoy doing together as a couple - like watch a favorite TV show together or listen to music together, something like that? Just something to re-establish your couple bond, apart from the situation of his medical condition and your need to be his caregiver?

If it bothers you, why don't you just ask him why he stopped calling you dear?

I would not place too much importance on that word, as long as he doesn't start calling you someone else's name :-) It's how he treats you that is important.

Ooookay - I take that back - I should've read your profile first... I didn't realize you were caring FOR your husband! Eek! Sorry about that!

Sounds like you need some time away with your husband, even if only for a couple of days. I know it's hard when you are caring for someone, but you need to make your marriage a priority. JMO.