I like the idea. The inciting incident is clear enough, she saves his life. Then as the first act comes to an end and rolls into the second, he begins to fall for her. I just think that the second act needs some work.
Although her drug addiction and past horrors seems interesting it feels a little vague. There's no real action there. I'd rather it say something like 'her drug addiction brings an ex boyfriend felon back into her life..." or something like that. (obviously this isn't your story, just an example) My point is just that this will imply action and a more aggressive protagonist who has a physical goal to overcome, rather than him trying to deal with her emotional baggage.
Hope that helps