Should I stay or should I go?? we have a daughter together :'(?

I wouldnt divorce him over it. I would simply say Husband, your family is your family. I have asked you several times to have my back with your sister and you wanted to be neutral. So, Here is what will happen, If you want to be neutral our house is neutral. If she comes over here and starts a ruckus I will ask her to leave and then she will not be allowed back over here until she makes an appropriate apology. If we are at someone elses house and she starts a ruckus then Daughter and I will leave and hopefully you will join us. I Will no longer stand and let Sister degrade me by causing drama. I AM your wife of 6 years and the mother to your daughter. I DEMAND the respect I deserve.