DEAR ANNIE: My husband and I have been together for 15 years. He has three children from a previous marriage. In the early days of our relationship, my nieces would often come and visit during the summers, and all the kids would play together. As everyone grew older, the visits lessened to just holidays. Fast forward to now, when one of my nieces is getting married. She invited my husband and me, and our two younger boys, but not the other three. I asked her if it was an oversight or if they were assumed in the family invitation. She told me that the four of them hadn’t really spoken in years,…