"he thought I'd 'forbid' him to go to that country again"
That's a pretty weird assertion.
Are you normally the sort of woman that would forbid her husband going to a country because a woman there came onto her husband?
How insulted do you feel to be cast in the role of controlling tyrant so he can justify his affair as starting with a "mistake"?
Not telling you wasn't a mistake, it was a deliberate lie.
I can see why an honest man would have chosen not to tell his wife about an approach he rejected - it could seem unimportant.
But in his case by the time he came home he regretted that he had rejected her and that is why he didn't tell you.
He didn't think you would forbid an honest man with good intentions from going away
He knew that if you knew that he planned to go back and shag her that you would not be happy with that.
His first mistake was before that, he had already given himself permission to go back and cheat.
But his telling makes his "first mistake" partly your fault.
"He did hide behind the 'The therapist said I need to say what I feel - I'm damned if I do and damned if I don't' position previously but I have said that he should have picked his moment and let me finish what I wanted to get off my chest first."
Self-pitying twattery.
I don't know how you didn't have a special rant all about that.
He gets to cheat on his wife, get lots of attention because of his difficult childhood, and then when the wife he hurt dares to get angry he says he doesn't love her, and THEN when called on his selfishness says he had to act in a controlling and manipulative way because of his therapy?!
Seems like he deflected the issue of him treating you like shit by making what should have been your recovery from his affair into his recovery from his own childhood.
His childhood abuse may be relevant, but it is not the whole story here and neither is it an excuse.
I'm not surprised you feel angry. I feel cross just thinking of that appalling reaction to the pain he freely chose to cause you in pursuit of his own enjoyment.