I live in a smallish town - only one primary school and only one class per year. My DC is in reception. One of the children's fathers was found guilty of looking at child sex photographs and online grooming of a young teen girl. He is on the sexual offender register. The mother has retained a close relationship with the father (they may still be together - I don't know her well enough). We have kids' birthday parties all the time and eg when she hosts one, the father is likely to be there. I don't want my children near this man. I just don't. I think she's keen for him to be reintegrated into the (quite small) community. AIBU is, I suppose, to make it clear I don't want him to bring their child to my child's party? (I will just make an excuse for their party). Also - is this unfair on my child's friend (who is obviously only 4 too). This is not something that is going to go away -- and want to work out how to manage it now. Please be kind - I absolutely know it is not the mother or the child's fault.