I completely agree with what Nepali Lahure said. This is probably just an infatuation. You can still date the girl but I don't think you should marry her. Nothing against her background, religion, and nationality, I just don't think this relationship is going to be beneficial to both sides in long term. You guys already broke up and patched up multiple times, and you said she still threatens with her ex boyfriends. If she was brought up in India, maybe things could have been different. But from what I see, you seem to be a more traditional guy and she is completely westernized (not her fault). If a girl still brings up her ex boyfriends, then that is a sign to not move forward in that relationship.