AITA for sending my step kids to their parents for Christmas?

I have 2 bio kids and 2 step kids. My 2 step kids were the products of my husbands infidelity. Their mother was a woman he met & started a relationship with while married to me. He knocked her up twice before he even divorced me. They are teenagers now, the youngest of all of the kids. My husband and I reconciled. We have been together for over 20 years. We have 2 kids of our own.<br><br>She has always maintained that it was my fault that he cheated. I wasn’t good enough in bed. I didn’t look good enough. But now she doesn’t hesitate to send her kids to live with me for extended periods of time. School breaks. Their summer vacation. She even sent them to live with us for a semester while she worked an internship. <br><br>The kids have never felt like my children the same way my bio kids feel like mine. I don’t want them to know this because I want them to feel loved and secure. However, they are not & have never felt like they are mine. I am their father’s wife, not their mother. I also don’t want to be a full time mother to teenagers. <br><br>The kids are all grown up. The 2 bio kids are in college now. I think this is a good chance to visit her family. She has complained that the kids have never visited their & her family because she has never had the money. <br><br>The 2 kids have never seen their paternal grandparents or aunts & uncles. So I thought it would be a good idea to send them to their mothers family for Christmas. It will be a chance to visit extended family. <br><br>She is devastated. She won’t see her kids for Christmas. She was planning to send them to our house. She has plans. She says that I don’t want her kids. I have never wanted her kids. I have only tolerated them because they are their father’s children. I am a terrible person for sending her kids away for Christmas. <br><br>Her kids don’t seem to care. ‘Christmas at grandma’s is fine.’ They aren’t upset over it. My husband is upset. He says that I’m the one ruining Christmas. <br><br>AITA?