I'm so sorry you are going through this. You have found the right place. There are so many here who truly understand what you are going through.
You're right. He's not a nice guy. He's not an honest guy. He's secretive and disloyal and non-empathethic. Multiple times.
IMO, it's time to take action. You've gone the counseling and "let's try again" route and that didn't stop him from doing what feeds his needs but hurts you.
Notably, he only scrambled for his counselor after you discovered what he'd done. He didn't scramble when he felt the urge to cheat. So, seems more like damage control than a real effort to stop.
Right now there are no choices for you without consequences, and I'm so sorry for that. If you take no dramatic action, you are likely to continue to be the phone police and will likely eventually find he's done it again (or he'll get better at hiding it). If you take action, it will be uncomfortable and scary. Maybe you ask h to stay somewhere else (with one of those good friends you trust?). Maybe you pull up stakes and head back to the UK and your own support system.
IMO, you need to get your ducks in a row: see a lawyer or 2 to figure out what divorce would look like. Get a counselor for yourself. Get a support system around yourself.
You don't have to rush into divorce. You don't have to do anything. And I support any decision you make, and so will others here. It seems like you see the really crappy writing on the wall: it looks like this is just going to keep happening. And you aren't okay with that.
You haven't done anything to deserve his selfish choices. That's on him.
A side thought:
We tried couples therapy a year ago and she mainly focused on me and how I don't have a support network.
Is it possible that the counselor was trying to make sure you were supported if he didn't change? Maybe she wanted to make sure you really felt you had options beyond just staying because you would have a support network.
Your husband seems to be banking on the idea that you won't leave (or make him leave) because he's not stopping himself from betraying you.
Again, I'm so sorry. Hugs to you.
[This message edited by BreakingBad at 1:40 PM, Friday, December 15th]