My 65th birthday and no one remembered. How do you handle it?

I would suggest that the next time a special occasion comes around(not just your birthday)that instead of sitting around and feeling sorry for yourself, that you find someplace near and dear to your heart, that you can go do some volunteer work at, like a soup kitchen, homeless shelter, animal shelter, meals on wheels etc. You get the idea. You'll be amazed how reaching out and helping others will turn your frown upside down! And you may just come to not dread these special days after all.
Happy Belated Birthday!!!

I haven't had anyone in my family acknowledge my birthday in years. Yet it's look to me to have a party for one of the kids or some other family member when it's their day. I remember my mother and a couple other family members wanted me to have a party for my SIL a few years back when she was turning 40 years old. You know what my response was? I told them we should throw her exactly the same kind of birthday party I had. Then, oh, wait that was nothing. My mother and some family members were actually resentful that I didn't throw her a party.
I turned 40 and got absolutely nothing. I have a few friends but none who are close enough that they would do anything either. My neighbor took me out to dinner. My family did nothing.
It is what it is and you're not alone. For what it's worth, I'm wishing you a happy birthday. I hope you have many more and that they're all filled with joy and very good cake.