My sister in law who was at our wedding and now lives in the house we were married in is so selfish. We have had a difficult relationship from the start due to her need to be in charge. She was married the January prior to our wedding and we dressed formally for it and were respectful. Hubby walked her down the isle. We called everyone a few months later to share our engagement and they 5 weeks before the wedding posted about getting the license. I was customarily cussed out for not telling her so she could come. She showed up to the wedding in a pair of men's basketball shorts and a tank that was semi dressy. She questioned me about my panties and even changed all the arrangements while I was getting ready. Yesterday she got engaged to her girlfriend of a few weeks. Posted pics online and announced publicly. Never called or sent a text to us or even mentioned that she was dating another new girl. (She was married and divorced the year we were married.) This is her 3rd engagement in 3 years. Tonight she messaged my husband to inform him she is getting married to this girl on our Friday September 13th, 2019. As in our anniversary and our renewal date. She laughed and said oh well about our plans. Her mother favors her over my husband and so I feel like the family will side with her though it will probably not be her last wedding as she doesn't settle down well. I am wondering do I cancel, reschedule, or tell family to pick? I have about 3 weeks to decide.