Hi everyone. Im new to Mumsnet but really need some advice. We have been having major issues with my partners ex regarding her contact of the children. (In a nutshell we have a court order to state the children will live with us full time and see her when we feel it's appropriate. She wanted them at weekends but because she didn't turn up at court the judge said she has no say) Anyway in the 2 years I've been with my partner she has had 4 new partners, 3 of which she has been engaged to. The new partner has a child in foster care and won't disclose to us why apart from shes not allowed to be around children on her own. This caused us major worries and we said my partners ex could only see the children if this new woman was not around. My partners ex refused and so hasn't seen the children. We have explained our reasons to the children (theyre 10 and 15) and they do seem to understand. After a month they were engaged and then after weeks of abuse she went completely silent and bearing in mind it's the school holidays hasn't asked the see the kids once which we thought was strange. Last night we found out why...a mutual friend let us know my partners ex and her new partner are expecting a baby together. The sperm was donated by someone they didn't know on Facebook and it's just thrown us both off course. The kids are holidaying with nanny and now we have this massive thing to let them know which has got us both down. We asked their mum if she was going to tell them and she just told us it was none of their business. Do we tell them or hope she will see sense and explain to them? It's a very complicated situation and it breaks my heart that she won't see them but is happy to just have a new baby. How do you explain to a child that this woman isn't supposed to be around children yet is having another one? Any advice really would be appreciated.