I see a GF who has crazy boyfriend/stalker...help needed

Hello to all
I will try to keep this thread little bit shorter so you can read it better.
Recently i met a girl who is few years older then me, she has a sort of boyfriend but she doesn't like him at all, she wants to break up with him for over 1 year now but he is still stalking her in some way and somehow they end up again together...long story :)
Anyhow, what is your advice in secretly dating this girl? I was with her few times, but i am always on needles sort of speak if he will come, or he will call her or something similar and he will catch us together..I like the girl, but i am not in love with her or anything, i would love to hang around with her and see how it goes, but this guy is problem..

She clearly states even to him that she doesn't want anymore with him but he is like a crazy person who is opsessive over hear and he always forgives her all and wants to come back etc..

She is little bit wild about that, and i think she likes to manipulate some man...anyhow i don't want anything serious with her because i don't want at the moment any full time relationship, but again i can't see her at all even for sex if i have fear each time that he will bang on door or something similar...

What is your advice and have you been on similar situation?

​​​​​​​Thanks

She's lying about not wanting to be with her BF to keep you around. She's monkey branching with you...if it isn't you she will monkey branch to someone else. she's that kind of girl. And like I told you before, her BF is going to mess your face up.