The reason we have the epithet 'dirty old man' is that there are a lot of them about. We have some rather strange social attitudes to sex, now that the internet has arrived and many people use it for sexual titillation. I am not sure your kids would find that much more than amusing.
Spying on neighbours, is a bit more 'creepy' but my guess is that it is what people did more of, before the internet happened.
Goodness only knows, you can see practically all of anybody on TV now, or rolling in the gutters on a weekend outside of nightclubs, attitudes have certainly changed.
I wonder how lonely he is?
You are at a time of life when you can make a new life if you choose. Make sure first, that you will be secure financially and don't lose out on any pension pot etc.
I think, difficult though this is, he may have been swept along by a tide of changing sexual mores, while you have stayed somewhere, prettier. Thousands of 'what the butler saw' machines and sea side post cards can't be wrong!
Take a step back if you can and try to balance out what is the best for you, a new life, maybe, your old life, with a 'dirty old man', maybe.
My ex was a womaniser, at least a peeping Tom isn't promising some impressionable girl the world, at no risk to himself.
I hate the pornography world............but it is out there and is rapidly becoming a normal art of life........or rather, a more easily accessed part of life.
This is about what you want. Nothing to do with the kids, they live in a different world, and if revelations did hurt them you would just feel guilty about that too. is there any real difference between all the potential exposures??? Not unless they make you feel much better and are totally predictable.
Do what makes you feel safe and happy. 'Never apologise, never explain' springs to mind here.....you deserve every happiness.