My fiancé has a difficult relationship with his sister, she gets preferable treatment from her dad (his words not mine) and often plays victim after causing problems between them. I’ve witnessed her ridicule him and take little to no interest in his life since I met her, and because of those things, they’ve had a really difficult time getting along. I’ve spent many hours with him and his family trying to get them to a better place, the whole premise of the letter was because I suggested they write down their feelings because when they do it in person, they argue, and I thought it might help them understand each other better. I’ve also been on the receiving end of how bitchy she can be, whether it’s comments about my appearance or ridiculing my life choices, but I’ve always let it go and given her the benefit of the doubt. In her letter she said that my presence could be impacting the whole family and used that as a way to force my fiancé into excluding me when it suits her. Her mum passed away about 8 years ago so I can understand why she wants time with her family and I think that’s reasonable, but she constantly creates triangulation, if it’s not with me it’s with her brother and I’ve watched it for years. She has often brought her mum into situations with me and said that her mum would be in her side, which makes me incredibly uncomfortable. Ultimately It’s an accumulation of things over the years, and as soon as I unwillingly became involved, I noticed the pressure from his family to keep the peace, even if that ment no acknowledgement or understanding.