Sharing Information

I am divorced and my 3 year old goes to an at home daycare run by my ex-husband's aunt & cousin. My ex became engaged a short time ago and the day care is now providing information addressed to both my ex and his new fiance. I asked what their policy was concerning sharing information with people outside of the parents and was told they provide it to the household. While I understand that my son will soon have a new step mother and that she will be involved in his life. I told them I did not want information addressed to her and that my ex could provide information to her if he wanted, but that it wasn't their place to include her on communications. I am incorrect in thinking that they should not be able to address information or provide it to anyone other than the parents/guardians? I want boundries set in place concerning my child set between myself, my ex and his soon to be new wife not his daycare. Please any policies on this would be helpful.