I need outside perspective on this family dividing issue. This will be long but I'll try to be as concise as possible.
In the early days of our relationship. my DH told me about his sister's allegation of sexual abuse against her stepfather. SIL is 21, and made the allegation when she was 16, and said that her stepfather had abused her from the age of 12-15. However, DH was under the impression that the allegation had been false, and swept under the carpet. MIL is still with her DP, and from very early on I got the impression that MIL does not really like MIL, and I know her grandparents dislike SIL.
In the time before I got pregnant, SIL began talking to her stepdad again, and staying around his flat with MIL. When I was pregnant with DS1, the idea that the allegation was being ignored started to bother me even more than it already did, because MIL seemed to be anticipating looking after DS1 with her DP, and that was not going to happen until either MIL left her DP, or SIL admitted lying. Now, SIL and I did and still do not really get on, so it took a long time for me to ask her about it. She said she had been telling the truth.
After having DS1, the idea of having the stepfather anywhere near me or DS made my skin crawl and the idea that MIL had not only not believed her daughter but stayed with her DP made me feel sick and worried about her judgment. I discussed this with DH and the decision was made to present MIL with the choice of leaving DP or me cutting contact with her. An almighty row ensued, and I cut contact. DH slowly cut contact as well, something that I made sure not to encourage, as it had to be his own decision. He has not spoken to her since the end of 2012.
So far, so horrible. But now SIL comes around occasionally with tales of how her stepfather has bought her expensive things, and how DH's grandparents now want nothing to do with him. I would hate to disbelieve her, but I don't understand how SIL can stand to be in the same room as him, let alone share food from his plate and sit on his lap, as I witnessed before everything kicked off. Furthermore, I cannot believe that the stepfather allows SIL in his house since she has not retracted her allegation.
I don't know what I'm asking here. This situation is entirely fucked up.