OPTION-1:
1. Prolong the relationship and accumulate evidences that she was staying with you with unconditional consent /voluntarily. Once this is done sufficiently, THEN proceed for legal action.
OPTION-2:
2. Let her know indirectly from some outside sources that you have some incurable diseases (failing kidney, AIDS, Heart Diseases etc.... ). When she comes to know, she will automatically ditch you, permanently and your purposes will be achieved, without any legal hassels.
Keep Smiling .... Hemant Agarwal
VISIT: www.chshelpforum.com
Since you did not marry there is no legal hurdle in saying "good-bye" to each other, discuss openly..
Don't fall prey to blackmail tactics adopted by the girl.