I aslo experienced conflict with sister-in-law, that time I had quarrel with my husband (her little brother), then she blamed me, she said blamed her brother is her matter. It was a shock to me. From then I totally hate my husband's family. And recall all my memory from beginning her family treat me was not nice. Even they help me on sth, they expect me to say thank you explicitly, understand inside heart is not working although I thought we are already family. From now on I won't visit my husband's family or any dinner gathering. Maybe once a year for Chinese New Year.