Father in Law gives threat everytime we have arguments

Mine is a love marriage.After marriage whenever I used to go stay with my parents for few days my inlaws started fighting and saying that I should not go this frequently . Also they would unnecessarily blame my parents that to have influenced me to fight with the in-laws which was not at all true and it was all in my in-laws head. within 4 months of marriage ,one day we had some argument and my father in law purposely called my dad to complaint about me. My dad and brother came and they were not aware of what has happened. My in-laws started fighting and misbehaving with my dad and asked him to take me from their home which my dad did. I returned to my husband but now everytime we have fight my father in law threatens me that he will file mental harrasment case against me & my family. My family has cut al ties with inlaws. Pls suggest what should I do.