I think she is using me to make my friend (her ex) jealous

So after my friend (Male 22) left her girl ( Female 19) for another one she suddenly started to text me (Male 20) and ask me if i knew that he was cheating on her. Ofcourse i wouldn't lie to her and told her what i knew. We started to text all days after that. After some months her friend tried to make me kiss her at a party( where she stole my phone and snapped her cleavage to her ex) after that i always got a feeling that she uses me just to make him jealous and i wouldn't want my friend to hate me ( now he does). So after that she started sending me some half nude photos and she made me fall in love with her real quickly to, but now everytime i ask her to come somewhere, she always finds an excuse, but when she wants to go somewhere she begs me to come with her. Past week we went drinking and i heard she was comparing me with her ex and told her friend that she is waiting her ex to see the story on instagram where she is with me. And she only inviting me to parties where are people i don't like and she knows that. I like her cause she "cares about me and helps me" but i feel like she is using me and makes a joke out of me... is she just manipulating me to make him jealous?

My friend and I had a similar situation when we were even younger than you all are. Let me just say that he and I have been friends now for almost 35 years and that girl is long gone. Don't blow a friendship over a girl, especially one as shady as this one sounds.

Well i think you are right,from the beginning i had a bad feeling about her but she kept telling me that im just imsgining it.