Background - Been engaged to DP for 3 years, together for 5, we have a mortgage and he has 1 DD from a previous relationship.
2 years ago, I caught him on Fab Swingers (I logged into his laptop which was connected to his iPhone, all history etc was synced) messaging disgusting things and viewing photos but no proof he had actually met anyone. In fact, it was him making excuses not to meet and there were no verifications. We split for a few weeks but got back together. We've been happy so far, despite his mistakes and he's never ever made a fuck up (that is aware of) since.
However... the dreaded feeling is back and he is being sneaky with his phone (popped in his daughters room for 2 minutes and came back to get his phone off the side) and every time I'm in the kitchen, I walk back into the living room his face is in phone and is reading the "news".
He's a very sneaky/clever person by nature and he's changed his settings on his laptop so his phone no longer syncs but he can say "babe, don't worry, check my laptop whenever you want to!" Well you've changed all the settings.
I know he's not meeting people, his car mileage is the same and his iPhone tracking is always where he says he is but he's clever, he knows how to hide stuff and I think it's all online.
How do I catch him out? I know the obvious answer is to leave but I'm not sure whether my anxiety is playing a part and making me overthink which in turn makes me paranoid but I'm not stupid. I know the clues by now.