Mainly our children, they are very close with him and he is a great dad to them, I don't want them to miss out if he was arrested.
You need to wake up.
You are failing your children right here.
He isn't a good father, he is an appalling father - a stalker, a voyeur and an abuser.
Cut the crap - you're scared of him and his reaction, that is utterly understandable but to weakly trot out the 'but he's a good dad, I don't want them to miss out' - fuck me, no.
Do you want to give your children the impression that this is excusable behaviour?
Do you want a son to grow up thinking that at some level, it's ok to harrass and stalk your partners because you really neeeeed to know what they're up to, up to and including setting cameras in their bedrooms? After all, that's what daddy did to Mum and she wasn't happy but hey, he was really upset?
Do you want a daughter to think that it's ok to be controlled and abused, stalked and watched by a boyfriend after watching and learning from your example?
Do you want either of them to watch and learn from this that it's much more important that pushy, creepy, sexually inappropriate Daddy have his criminal activities excused than it is for Mummy to feel safe in her own home?
I am sorry but if you had their long -term emotional health as a priority here you would be looking for any means to restrict and minimise the contact and influence this pervert has with them. He is damaging, full stop. Good fathers are not measured by trips to the park and bouncing on knees and smiley jokes. In fact, the fact that he doubtless does all this stuff at the same time as being a controlling sexual predator and a family abuser should be giving you the absolute horrors at him being allowed to continue his 'normal' relationship with them and possibly use them too as means of control while teaching them that it's ok, they should be on Daddy's side, Daddy loves you and that's why he needs to know allll about what Mummy is doing and what friends does she see... etc. etc.
You are absolutely failing them, properly failing them, putting them in harm's way, by not standing up to him and reporting him properly.
He should have supervised contact in his position as a stalker and voyeur. Simple as.
Good fathers