Well, I’ll offer a semi-contrarian view. What is it you’re hoping to get out of telling him? If it’s an apology, or even an acknowledgement of the truth, you won’t get that, so don’t bother.
If all you want is the satisfaction of letting him know he hasn’t pulled the wool over your eyes, AND you don’t think it will trigger him to do anything that would harm you, then go ahead - I understand wanting that satisfaction.
But I wouldn’t share anything about it with your kids unless they ask you directly. You’re not obligated to lie for him, but it’s really best for your kids if they don’t figure that out right now.
And yes, he’s probably trying to keep you apart because he lied to OW about your relationship. Usually they’re not bothered at all about waving the OW in the LBSs face, so this is probably the case. In which case OW is a victim of him too.
Just be glad you’re free to be in a much better relationship,
