Or is it completely 'wrong'? This is between two consenting adults obviously.
This is somewhat lighthearted. But I do wonder, is there ever a time where someone can just be too old and people would rightly question it?
It would purely be a bit of sex, I think. Nothing more. I fancy him by the bucket loads and he looks amazingly well for someone of his age. He is also frightfully intelligent.
If people saw us kissing goodbye, would they think it particularly odd that I look so much younger?
I'm really just after your personal opinion 
My mum thinks go for it. Sister thinks I'm bloody mad. Friend thinks it's a bit too much of a gap.