Polly, I remember some of your threads and through much of them it has been your hypervigilance and pain showing through.
Now that is not uncommon, when someone betrays you it's impossible to heal when they continue with the same behaviour. You must be thinking "tell me something I don't know."
At present you are trying to obtain some sort of control over another crap situation, you must be worn out with all this detective work, it's no way to live, but you love him.
At this stage in the game, you should be beggining to see your whole life will be like this, you cannot control him.
Is he a very attractive man, who has women falling at his feet?
So much harder than having an average looking bloke and couple this with your increasing insecurity and lack of trust, it must be like a living in hell.
Your confidence is shot, he has destroyed it, relationships are not a game to win, who is the better looking, who is doing the best at winning within the relationship.
They are meant to lift you up, make you feel safe, secure and wanted.
This man is making you feel like a loser and nobody should make you feel like that. You have children, you feel you need to depend on him but he is taking advantage of that.
He really isn't a nice person, you are, you are better than him, you don't create pain for him intentionally, he does and never will he change.
You could keep catching this lathario time and time again but nothing will change.
Your mindset has to change, to expect better for yourself.