Yeah, it's a fulltime job running yourself ragged trying to stay 2 steps ahead of them. Been there, done that.
Of course, you can drive yourself nuts monitoring the usual avenues that they used before D-Day, but they're not going to use the same ones again if they're still in touch - and possess more than 2 working brain cells. They'd have to be idiots.
I had blocked the OW from being able to call or text my ex on his cell, but she just worked around that and called him at work (which I had no control over). I think she also started using a friend's phone to text him when she couldn't on her own. I then blocked her from being able to email him when she resorted to email, and since he's not smart enough to be able to create a NEW secret web-based email account (which can be done in about 4 minutes) that became a dead avenue for them. But anyone with half a brain can create a new Yahoo or Hotmail account in literally no time flat.
Also, if your husband has an iPhone or a Smart Phone, there are lots of apps you can download to use and chat with, send files to each other, video chat with each other, or text each other - and none of it shows up on your cell bill. None of it.
Yup, thanks to modern technology, it's made cheating the easiest thing on earth to do, now.
Don't knock yourself out monitoring the accounts you already know about, Tremble. They'd have to completely brain dead to use one of those, now.
An option is to get a VAR (voice activated recorder) and hide it in his car. It's most common for cheaters to talk on the phone when they're alone in the car on the way to or from work, etc. etc.
It's unfortunate, but it's extremely rare that the cheater and their affair partner truly cut all contact after D-Day.
I think it SUCKS having to drive ourselves insane trying to monitor their sleazy behavior for our own peace of mind. I think the clear majority of us all go through that stage, however.
As far as him not knowing how deep this would cut when you found out, he knew it. But the thing is, cheaters truly believe they WON'T get caught so they won't HAVE to deal with the emotional fall-out. They know exactly how hard it would be on their spouses, and that's why they work so hard to keep it a secret. Otherwise, they'd come home and brag about it to you. So he knew. He was just hoping YOU would never know. That's Cheating #101.
It takes an incredible amount of energy to continually monitor someone after they've been caught cheating. I know exactly how crazy-making it is and how strong the compulsion IS to keep at it every single day.
The one thing I can tell you that helped me release a lot of that crazy obsession was coming to the realization that if someone really wants to do something bad enough, they're going to find a way to do it. Sure, I can throw a temporary monkey wrench into the works and thwart them from contacting each other for a day or two (blocking her number, blocking her email), but the simple truth is that people are going to do what they want to do regardless of how much we try to interfere.
Period.
And I also realized that I didn't WANT to try to control him like he was some 11 year old boy who needed me to monitor him to keep him from misbehaving. It's not my job to control him and make him do the right thing. If he doesn't WANT to do the right thing, then I need to find a way to deal with that, rather than compromising my mental and emotional well-being trying to make sure he's behaving 24/7.
That made a huge difference once I made that realization, and I was able to let a lot of the anxiety go. But I also left him, so in all fairness, that was a great motivator to let a lot of it go.
Good luck to you Tremble, as you try to navigate this crazy path we all find ourselves on.