If possible it would be ideal to have your husband there the next morning he comes and have him appear just as the dad is taking off his shoes and you telling him that won't be necessary since he is not welcome to come into your home anymore. That is a place for the children not for the parents.

I would really be wondering why he is doing this as his child obviously doesn't need any reassuring and even that isn't a good enough reason. I hate to paint all guys with the same brush as they say but what is he getting out of watching all of those little kids, creepy for sure. When he knows you don't want him there and he still does it that is not acceptable at all. Can you block the door when he comes and ask him to hand the child directly to you and to not set foot in the house since he doesn't seem to know how to turn around and leave at drop offs. If he gets offended and leaves with his child probably even better. Time to replace for sure.