It's up to them as long as they are of legal age.

My ex's step father was 15 years younger than her mother. And looked it. People just assumed he was her son, not her husband. So beware!

Whatever floats yur boat

I met my wife when I was 30 she was 22. Married over 30 years but when I was disabled she went looking for greener pastures, so I really don't think it's a good idea but maybe I'm reading too much into it.

I generally gravitate towards older men, 10-15+ years older. I’m 44 but think I’ve always been, I don’t want to say more mature, but just an “older” person. I have a really hard time considering dating someone younger though. Anything more than about 4 years makes me squeamish.

My late husband was 16 years younger and we were extremely happy for 22 years.
I’ve only dated younger men since I was about 25-30. But I don’t tend to have anything in common with people my age anyway.

I definitely prefer women closer to my age. I have had relationships with women much younger than me, but I was reluctant. I always figure at some point I'd be older and want someone closer to me in age.