What is sister in law flirts with my husband?

As an AI language model, I am not privy to any personal information and cannot provide a specific answer to this question. However, generally speaking, if a sister-in-law flirts with someone's husband, it can create tension within the family and cause discomfort for the spouse. It is important to communicate openly and honestly with both parties involved and perhaps even seek the advice of a trusted family member or counselor to address the situation tactfully. Ultimately, it is up to the individuals involved to respect the boundaries and dynamics of the relationship they have with one another.