HI, fell for a girl knowing very well, she is in a live in relationship with another guy. We came close and close as she was getting unhappy and unsatisfied with her current livein partner. I fell for her emotions and got involved with her emotionaly. Started thinnking and living only for her and she responded.. but she then asked me to marry suddenly one day at which I told her that I won't be able to do that. Now she saays she is in love with me, doesnot want me to go for any other girl, wants me to take care of her like a lover and a friend, wants to tell and confide in me.. in short tells me she is in love with me but can only be emotionally involved as getting physical with me makes her feel guilty and unfaithful to her live in partner. Though I on my part think, when I am totally in love with her and give my 100% so why should I settle for 50%. ( only emotional supprot).
Can't leave her and when I talk about being jsuta friend or moving over her.. she starts emotional blackmail. Please suggest what should I do? Am so confused

Move on.

Find someone who is not going to use you.

As you said,why settle for 50 %, but 50% of what...

Do not tolerate anyone using emotional blackmail on you... walk away.

Wid 50% I mean.. I on my part only being happy providing her emotional support and not getting physical support from her with her own wish and will, and for which I crave so much.. as its my first experience of getting physical with someone.