Originally Posted by
J_9
Rather than reading the words written on this thread, I am going to "read between the lines," having been in a similar situation.
To the OP, I see that you are a very caring husband and father/step-father.
I don't see a problem having a discussion with the 11 year old if she is asking what is going on, but you shouldn't bring it up either. Talking to her at her appropriate age level is okay. It seems she feels more comfortable talking to you than she does her own mother. She needs, and deserves, comfort when things are disruptive. She needs stability, which it seems that she is not getting from her own mother.
It's very clear to those of us who are not engulfed in this situation that your wife is having an affair.
I'm not one for ultimatums, in fact I despise them. But, it appears that this is what you need as she is using you for her own benefit. It's counseling or divorce. She has 3 days to give you an answer. If she doesn't give you an answer in 3 days, file for divorce. It appears you are the only anchor in the lives of the child(ren), so make sure that you file for custody as well.