OW crossed the line definitely!!!! She is not the mommy. I mean, you two are not even D'ed yet!!! I mean, in the long term, if OW and your H get married and she is the step mom (sorry if this is harsh words to hear), she will need to earn her role as a step mom before she can do such things!!! Sorry to say this but I think your H seems to be weak in front of her and cannot "control" the situation when he is there with her? He is the daddy. D4 cannot refuse as she is so small.
