If you knew this women was a nutcase prior to getting married, common sense is that you should have discussed the issue about the child in regards to continued visitation and discussing it with the mother (A written agreement). From the way you are explaining the mother, I would not want her around my own children. Your husband knows this is an issue, if he doesn't have the integrity to put you first then that says it all. If its that important to him to continue to see the child while you are unhappy and its causing conflict in your household, I would walk away. Is it really worth it to put your own children in a bad situation if this person decides to be vindictive to hurt you? Seriously think about the outcome of the worst possibilities. I would never allow such non-sense come into my home disrupting my childrens home life. Is the love for your husband greater then being accused of child abuse to the point of losing your own? The mother of this child is not obligated to do anything, legally you cannot force her to give any visitation.
I would definately walk away. Good Luck
I would definately walk away. Good Luck