How do you tell someone you don't want their child playing with yours?

Well, I have a friend who I know from a previous relationship. She was my ex fiancé's sister in law, who has a now 7 year old son. Long story short, my fiancé and I split over him cheating but the sister in law, (we can call her meg) ended up knowing my now husband! About four years have passed and like I said I'm happily married, have a baby on the way, and now have a 6 year old step son full time. Meg has always tried to keep our friendship going, especially since she also knows my husband.She has also tried to set up play dates with my 6 year old step son and her 7 year old son. My husband and I have both agreed that we are not comfortable with having play dates for multiple reasons which I will explain.Meg has chosen a very different parenting style where she does not follow through with what she says, there is never repercussion for something done wrong, there really isn't much parenting going on at all. As a result the child is completely out of control, he doesn't listen, play nicely, he is rough, he says inappropriate things, and he's just wild in general.We also have a big issue with him not being vaccinated. I've managed to put off these play dates with my step son largely in mind but also my soon to be newborn baby who I certainly do not want this child to be in contact with because of him not being vaccinated. So I don't want to open the door now and have to deal with this more when the baby comes.I should also talk about my step son. He has been through a lot of trauma this year. We used to have 50/50 custody shared with his mom. Mom had been neglectful to her children and abusive to her husband. As a result we now have full custody and she is not legally aloud to see my step son at the moment. His whole life has been changed! He had already been shy, but is more so now. He is a very good child, almost never misbehaves. He lives with us full time, he goes to a new school, and he left a brother behind with his step father. He's still adjusting to all the change but is doing very well. He has never met Meg's child so it is not as if he would have an interest to play because he doesn't know Meg or her son.Meg has never done anything to make me want to be mean to her to put her off, but I have tried my best at avoiding a friendship. She comes with trouble that I do not want to be involved with nor do I want to involve my family with. Not to mention she lives with my ex fiancé's family and I really don't want to go there! Just this morning she messaged me and asked me if I would want to set up a play date with our two boys. How do I tell her that I am uncomfortable with that without sounding like a jerk? I don't want to be mean to her but for all reasons above I really do not want our kids together and I really don't want to be friends with her either. Help me!TL;DR Old friend with terrible child wants to set up play date with my child, how do I tell her no? via /r/Parenting http://ift.tt/2x70Rof