Needing some feed back.
We are less that two months away from our wedding, my fiance and I maintain a good relationship with each of our families. Or so i though, a few weeks ago we were at a get together at my fiances sisters home. Him and I had a small argument and resolved it fairly quickly, and discretely between the two of us, hardly anyone knew we had a disagreement. An hour later I walked into the house to use the restroom and his brother in law started yelling at me, and getting very hostile over the fact that my fiance and I had a disagreement. I responded him with "what happened was not their business" It of course escalated from there and his sister got involved. She began being just as hostile and say some pretty harsh things. We left and we are not talking to them, my fiance has tried to reach out to them and asked that they apologize. However, his sister thinks that she did nothing wrong. We have been together almost 3 years, if she had a problem I would have expected she pulled me aside and spoke to me personally. We get married in two months, she said they will not be attending the wedding now. What happened, happened and we can't go back. They do not want to own up to their actions. But I worry later down the road my fiance will resent me for his sister not being at our wedding. I know this was not my fault however the fight happened between the brother in law and I. I feel stuck, I want my fiance to be happy. But I also have respect for myself and do not want others to think it is okay for them to treat me badly.