The other scenario from the script at this stage is he plays the victim instead of getting angry. Guilts her about breaking the family up, not giving him the chance to make right to her after what he views now as all a massive mistake and poor decisions on his part. He will act the little boy lost, realising how much OP means to him. Yawn zzzz! What this does is put pressure on you to reconcile/give him another chance etc. However it is all empty words. He wasn't sorry when he was doing it only sorry once he's been caught out.
I'm very sorry but from experience and depth of his involvement I highly suspect he's not ended it at all, cooled it maybe for time being, put her on back burner until he has got you sucked back in and under control again. He will in a few weeks give you a hard time if you mention the affair, hoping it can all be swept under the carpet and he can return to OW who is his primary partner and love interest, thus relegating you to OW status again.
If you give an inch this man will continue to manipulate and lie to you. HE IS NOT YOUR FRIEND.
You may find this all hard to believe as you are judging your views and decisions still on the man you thought you knew, not the man he has shown to be. I am so dreadfully sorry OP. I feel your pain and know that sadly there is only one way you will ever feel whole again and that is by getting rid of the cheating low life. You and your children deserved better, so much better and this all feels like a nightmare you just wish you could wake up from or run away from.
I have been in your shoes and would not wish this on my worst enemy. I did contact OW and we chatted for several hours. Of course he had minimised everything about their relationship to me including the sex, depth of affair and all the intimate details. I was utterly heartbroken, came home and was physically sick at what I'd heard. I then drank myself unconcious, howling and raging like a baby on the bathroom floor through the night. If I hadn't been so drunk, I would have selfishly thrown myself on the local train tracks. I just couldn't get my head round it all. What you are going through is the most horrific betrayal, a pain akin to losing someone through death. None of this is your fault at all. It was his decision alone to cheat. Never for one minute forget that.
For your own sanity, you need some space between you. I would also do the 180 as it will help you cope: beingabeautifulmess.wordpress.com/the-180/
If you know who the OW is I would contact her to get a truer picture of the affair and if indeed he has ended it with her, but keep your own counsel whilst talking to her. She is not your friend either. You might not like what you hear but at least it will give you clarity. Most betrayed wives/ partners do need to know to get an understanding and for many this helps to make that essential decision to move on.
Really routing for you @Pippa49 and hoping you can absorb some of the sage advice from other Mumsnetters on this thread who have all been in your shoes.