Someone causing drama with me and my extended family

I cannot stand the drama. My husbands friend got mad at me and started this horrible rumor going over to my sister in laws house and getting her involved. I have a son with her brother and all I wanted was a good realtionship. Now I feel so upset that at her age she would even carry that rumor or even have anything to do with thoes people who are trying to break me and him apart. My husband doesnt belive it the timing is to perfect for this person to start this rumor as he got back together with his x and knows I dont like her due to rude unsavory things she has done to me... I want a good realtionship with his family but I keep failing to do so. It hurts and depresses me. I know I shouldnt put anymore energy into this because I cant change anyones mind and what they choose to think of me. I guess what im looking for is advice on how to not let it hurt or depress me. I thought she wanted to create a good family environment for the kids not play highschool games

a rumour with no truth is laughed at,noone believes it,its going to die out,dont worry,you be positive and live your life happily