When it comes to the loves and losses of our children, wisdom demands unfashionable restraint. However difficult, we must allow our children the independence of making their own relationship choices. Even if we don’t always agree, it is our role as parents to support our children’s decisions as best we can to avoid them resenting us for interfering. It may be a good idea to see things from your daughter’s perspective. For whatever reason, she split from her ex-boyfriend because things never worked out. Would you rather she be unhappy in a relationship because it suits you for her to be with someone you approve of?
I predict even if you invited your daughter’s ex-boyfriend for Christmas, he would decline, as to be in the presence of your home could ignite painful feelings for him, which you may not have considered. You are not responsible for him, and maintaining an attachment could be delaying him from finding his own future happiness. For now, perhaps you could meet up with him before or after Christmas on neutral territory with a small gift, this way you won’t feel like you’re completely disowning him, but gently distancing yourself.
I suspect other family members are mirroring your feelings. For your daughter’s sake, and to be able to enjoy a relaxing Christmas, do try to make her new boyfriend feel welcome. You could surprise yourself and even get to like him. Nevertheless, try not to become too attached as your daughter may well trade him in for another at some stage in the future!