I have been with her older brother for 7 years and they are very close. We would all spend a lot of time together, and her and I would do things together. Over the last year there started to be a lot of tension between my fiancé and her, and because she and I were friends I was stuck in the middle. Then my fiancé started to take his anger for her out on me and pretend like everything was fine when we saw her. Soon my relationship with her started to change and I viewed her differently than I had before. I began to have feelings of resentment and would take deep offense to comments she would make towards me that I would normally just blow off. Tension has built over the past year and now we do not even speak at family functions. I never thought we would get to this point but I feel like so much has happened and I have no desire to be around her at all. I thought maybe I just needed time away but every time I see her I wish she wasn't there. I feel really bad about it but this is how I feel now.

Your relationship with both of them has changed.

Where your now fiancé used to be a friend, he is not. Where his sister used to be also a friend, she is not. The relationships have changed.

What you have no control over, is how your fiancé and his sister get along. You should make it very, very clear that they can fight their own battles, and to leave you out of it. Be careful not to choose sides, or appear to choose sides, and come between them that way. If push comes to shove, your fiancé should come first.

You would do well not to accept being the monkey in the middle, because it will only cause resentment and confusion. If you don't contribute by listening or trying to be a mediator or referee when they fight, they will have only each other to face, and that is how it should be. They are adults, let them figure it out.

It is never easy when you lose a friend over a boyfriend. Even harder when that friend is your (now) fiance's brother.

But, people change, and relationships change. My best advice to you is to dial out, not participate with either of them when they try to engage you in their arguments, and instead say, "I don't want to be in the middle of this. Go and talk to her. (or him). They will get it eventually if you stick to your guns.

Take the high road here, you won't regret it.