P,sorry for repeating my q about wanting kids---I misread an answer!
Now, I just find it hard to think your W is actually evil although she may be acting like it. Let's brainstorm explanations for not going to see your mum:
1) W feels guilty and thinks your mum must hate her for what she did& is afraid to face her
2)W doesn't want to leave OM alone to go visit
3)W needs to get time off from work...what are other reasons?
As you can tell, I am not a believer in a cookie cutter one size fits all plan, so if it is eating you alive not knowing why your W doesn't want to see your mum, then find a way to ask her.
You could send a text or an email to find out, prefacing it with a message about how this situation calls for breaking NC temporarily.
Others may disagree though.
me,34 exH,34 S,16 months S:3/31/09-left for OW started DBing 10/09 d final: sometime 10/10 current: http://www.divorcebusting.com/forums/ubbthreads.php?ubb=showflat&Number=2022856&page=1 met in 2004