Agony: My husband has alienated us from his family

My husband has successfully managed to alienate us from his family. When we were dating, I got the sense that he did not want me to get too close to them. He is the first born and made it clear he wanted to focus on his nuclear family because he grew up in poverty. He said his siblings, most of who were still in school, some jobless would keep asking him for financial help, and he was fed up. He had just landed a UN job, and I was more than happy to meet a man who put me and our future kids first. We were rolling in money. We have been married for six years and his relatives have only come to our home once, right after our wedding. We had also just entered our newly built storied house and I only saw it fit to invite his family over for the house warming party. He was not happy about it. He told me never to invite them into our home behind his back; that he hadn't told them he had built a nice house. Today, his five siblings have finished school and are well placed in the job market and have families of their own. They have family gatherings and outings and are really close, but we are not part of this happiness. I follow some of them on Facebook and I can only admire from a distance. My children have never met their aunties, uncles and cousins. It is lonely. Both my parents are no more and my only sister lives in the UK, so it's hard to have that relationship that can only come from family members. Recently, our youngest was so ill and was admitted in ICU for three weeks; I saw my husband cry and it broke my heart. We had no one. Friends would come to visit, but they too have their own lives. I tried calling one of my husband's sisters to get her sympathy and support, but all she said was "sorry, I'll pray for your family." She did not visit. By association, I have become my husband's accomplice in this foolishness, but I want things to change. I want our children to know their relatives before it's too late.

Please advise, Winnie