When does an in law stop being an in law?

my husbands's first wife divorced him and remarried. She is always sticking her nose into his families' businessess. She still refers to herself as his parent's daughter in law. People are always thinking they are still married and that she is his wife. They have been divorced 15 years and he's been married to me for 10! Am I wrong to feel disrespected? Should I ask my husband to say something? We didn't want to cause a family rift (there are adult children) and have been very tolerant but I am getting pretty fed up with this and about to call upon my inner b***ch. Her second marriage failed and I am wondering if she thinks she can get back with my husband (not worried about that)....What do you think? Am I being over sensitive.?