My XH forced my kids to lie to me about OW's as well. The worst was when my D11 who was 9 at the time came home from 3 weeks with XH, I picked her up at the airport and took her to lunch at her favorite place, we were sitting there and she said "mommy, can I talk to you in the bathroom" I was like, "what's wrong, just tell me here" She refused so we went in the bathroom and there she said "mommy, my heart hurts sooo much, I just can't take it anymore, Daddy made me meet OW (she said her name) and told me not to tell you, that you would be mad at him and at me, but I can't lie to you and it is hurting my heart too much" I just grabbed her and held her really tight and told her "I would never, ever be mad at you for that, that is Daddy's fault he did that to you, not yours, I love you very much and you are just a little girl, your heart doesn't have to hurt anymore, I am not at all upset with you" We went back and enjoyed our lunch.
But, there are many other things he has done, could type all day, that has destroyed HIS relationship with HIS kids!! It is all about him and what he wants to do (or it was, he has gotton so much better since that OW and OW#2 are gone), but those things he did will forever effect our kids and have changed how they view him forever, and it is beyond sad!!
I have an even worse story about how he made D17 lie to me too, but again it involves an OW. I understand your pain with this, I fought to keep and will forever fight to keep horrible, awful, nasty, bad influence, bad morals, woman away from my kids, if he ever wants to chose a woman who is decent, we will talk about her meeting the kids, but so far both have lost custody of their kids, have no contact with their kids, have broken up marriages, beat their kids, drink way too much, sleep with many, many men in front of their kids, etc. They are just not people I will accept and I have the power to keep them away and I will. Not everyone can do that, and if they can't then the conversations with the kids needs to be very open and honest about morals and right from wrong. This is all just my opinion, of course.
A
Me-40 XH-44 T-21 M-18 Div-19 mo. D-18,S-15,D-11 Bomb-7/07 EA,PA Mvd out-9/07-to give me space mvd back-12/07 mvd out-7/08 back with OW since 2/08 OW broke it off-1/10 in and out of tunnel and our life since!!