How do i handle the deceitful mother in law??

My mother in law likes to cause drama... she's always looking for new ways to make other peoples lives miserable. Ive always just let it go and accepted that its better to just not get involved. But this last time she drug my family into it... I dont know what came over me but I snapped and now i can't even think of the woman with out all the hateful emotions coming back. Im having a hard time letting it go! I hate feeling so negative towards her and i try to remind myself that she is my husbands family but how to do you show respect for someone who has ALWAYS attempted to form some kind of clique against you... I want to be the better person but 7 years of drama is more then i can handle... I have no intentions of spending holidays with this woman but i know my husband is gonna try and talk me into it, and ill end up being the bad guy.