Someone lying about me

So I am in college. Fall semester 2024 there was this guy who always asked me to hangout and always tried to get me to come over and would approach me in public. Going as far as to ask me to come over when I was intoxicated and he was not. Well I didn’t like him and I never hung out with him. When I started talking to one of his teammates he told that teammate and a bunch of other teammates that we slept together(we did not) well fast forward and he asks my boyfriend(the guy I started talking to that made him start lying in the first place) if the place I work is hiring. My boyfriend told him I would quit because of the rumors he spread last year. He then denied the rumor and doubled down that we did have sex. Well I’m really tempted to dm his current girlfriend and let her know everything. I just need a good way to tell her. Or maybe I shouldn’t tell her. It’s just so disgusting to me please help.