My DH would like nothing better than to be a big happy family with all his 5 kids. With YSD22 and SS18 this is fine when they visit, but OSD23 has been a nasty aggressive divider. She spent some years not visiting us because of a grudge she and BM had against me (suited me, he went over to see her occasionally so he did not lose his relationship with her). Partly also possibly because BM had been telling her she was not DH's biological child so she may have had identity issues, who knows. However now she has started to try to come back into our lives (may not be unconnected with fact that DH and I at last have a proper sized house and she has finished college career in another location and has not been able to secure work -- she may wish to use us as accommodation. DH typically believes all that he has been told about she wants to make it up with me and become part of a family with us all, especially me whom of course she has apparently said she now really wants to be close to -- :sick: ). Her recent involvement began with attending our housewarming last December, where she caused no problem other than appearing to ignore me (as usual), and then she came by to stay in February, again causing no problem overtly but attempting conversations with me and attempting to cosy up to my sons 8 and 13. She actually followed us around the house. The 8-y-old does not know her but the 13-y-old saw her a lot as a baby and toddler, and would like her approval. OSD was trying to get him onto FB (which he is not yet) and generally make a separate relationship with him which I fear she can then exploit to divide and rule further. I feel she would love to challenge my authority over my own children in order to divide and rule in a new way. I would have no problem excluding her from my family life but for the biokids. I don't want her to be with them alone but I am going to find it hard to head her off without creating an atmosphere that could harm the boys or causing DH to attempt to manipulate also. She is possibly visiting DH tomorrow whilst I am out at work and I may come back in on her with one or both of my sons, unsupervised by DH after school. DH would not accept that she would be any kind of moral/emotional threat to the boys in a million years therefore, realistically, the only way to prevent him promoting their relationship would be divorce. This does not seem worth it bearing in mind she is so rarely here -- until now. It may all be over with these visits for another year after tomorrow but I don't know. How to assess the situation is difficult bearing in mind I have made a point of not asking about her life, her plans, her movements and so on.
Any advice anyone please, would be most welcome.