Ophelia,
You are doing fantastic.
One thing that doesn't sit right with me is your OH continual need to tell you how great the OW is.
There can only be two reasons for this:
1 He knows exactly what he's doing and is really trying to hurt you and get a reaction from you, so he can shift all the blame back on you, ie "she's totally irrational!"
2 He is not only trying to convince you, he is also trying to convince himself and in doing so, is to justifying his disgraceful actions. He knows what he did is wrong.
She is, on the other hand constantly extolling the positives of their break-up and how wonderful they managed it. Really, only a fool in lust will actually believe that utter rubbish. No one will ever tell you, no matter how amicable a break up, that they managed it well and are proud of themselves. That's delusional!
She is still on tender hooks with him, its still early days, in her mind he could still drop her and go back to his wife and two DCs. Don't for a second, think she hasn't thought about that. BTW I know this has gone too far for you, I am just as, an outsider highlighting scenarios that are very real.
I have followed you thread from the start, it does appear to me, that you H has actually behaved worse since the discovery of the affair.
Do not doubt yourself Ophelia, Its not all rosy in their garden.
Do you honestly believe, when your h is on his own that it hasn't occurred to him, what he has done. I know other posters may disagree with me, he is at the moment, still in the honeymoon period, this will change.
Going forward, your expectations of him should be much lower, expect the hurtful texts and nasty outbursts once he receives the solicitors letter. This will give you strength.
Many people have posted there should be at least a 6 month waiting period, as to when the OW meets your DC. I agree with this, Although you H must will try to dictate when this happens.
You mentioned, their activities in the Stationery office at work was a sack able offence, you could use this as a threat, to disclose to his boss and whom every you see fit, if he doesn't play ball. Believe me, if the OW hears this she will be terrified.
The tide will turn for you. You have good friends and family to help you get through this. Be proud of your DCs. Your H will be ultimately the loser in all of this. He may never admit this to you, but he will know it.
Their relationship will have many problems. Even though its all great now. Imagine the prospect of working together every day, being together every evening, talking about how great their life is, there's no more need for their lustful exchanges in the office, no more sexy hot emails, they have all evening to talk about it, minding different children every weekend. Her ex coming over for dinner. Its all to good to be true. He will grow tired of it before she does. It will grow tiresome. That day will come.
There are many great posters on this site, they are really an inspiration. Listen to them. Have faith in yourself and believe you will get through this and be a much stronger person for it.
All the very best.