Dealing with Rumors and Body Shaming in a Relationship

lately its been hard to control my emotions me and by s/o were doing just fine then rumors started that said inside certain things which never came out of my mouthm. and the one person that said it was the same person my s/o claims is a gossip queen and twists things. she basically just ruined everything i have been fighting. i am so hurt and then to be told i am getting fat and that im a heffer and if my.man still likes a fat cow has been getting to me as well. i am 125 lbs i use to be 96 lbs i had an eating disorder and a thyroid problem and i am finally at a decent weight and most of it i have been exercising so its mostly muscle and i just wanna cruel up and cry and go crazy!