Easier said than done when you say, "I want to be the bigger person" because they are throwing major shade about you. They feel its necessary to feel they can be better than everyone because they don't have that personal development, they dragged the past around so long, wanting to have a better recognition to the public eye, feeling sorry for themselves... There is a big list as to 'why,' but stand your ground, try to kill them with kindness, and hope for the best for them.