What is my move with this girl? Do I give up?

I will try and keep this as brief as possible... I have been dating this girl for 10 months now. I'm 24, she's 22. We have had a few issues along the way, her ex's were abusive to her, her step father abused her, she doesn't trust and is afraid of commitment. She wants to be a police officer and is attempting her third try at it and I hope she succeeds. During our dating I have had to prove I am trustworthy, and by doing so I have treated her like a princess, because she is to me. We have went through about 20 breakups, all of which eventually ended up in her coming back and saying she knew all along we would be together. She is completely in love with me, and I am in love with her. Over the last few weeks she was living with me, she was talking about marriage, getting our own place, saving for a house, etc. The other night she broke up with me again saying she needs time to sort her life out, and that she hopes we are together again when that happens. To let her know how serious and how open I would be, a few months ago I told her that I used to break the law occassionally before I met her, but I don't have a record thank God, and I have became a better man since being with her. She opened her arms and thanked me for my honesty, but now always dwells on that. This time when she left, I said I am not going to fight it, if leaving a man who adores you, admires you and wants nothing but a happy life with you then there is nothing I can do. I am so sad, but I refuse to call or email her. She came by the other night to grab her stuff, and I made sure I wasn't there. I left her 12 roses and her fav. chocolate bar with a note saying ';Take the time you need, I hope your heart points you back to me. Until then, I love you'; She wrote me the next day saying how much she loves me, that she believes in us, and if we are meant to be, we will be. She said this break will allow her to get her #%@* together asap. I am heartbroken, but being strong. What is my best move? I know asking how long until she comes back is an unanswerable question, but if two people are crazy about eachother, love eachother, trust eachother and see their marriage and family with them down the road, how long could I be waiting? She broke up with me Monday, and I was strong enough not to say a word to her for 3 days. Now she is writing me emails/texts saying that she misses me and mentioning all the things she loves about me and she is hurting so badly. I am too, but I am sick of having to prove I am worthy and being broken up with bi-weekly for no reason. She said she see's us married and a bright future, and she hopes it will work out. How will it work out if we're not together??? Won't being apart make us forget eachother? Why would it not work out if we are in love and see eachother together? What do I do in the meantime? Mind my own business, stay single and wait for my sweetie to come back?What is my move with this girl? Do I give up?
sorry but I really don't think marrying her would work out... if you guys break up all the time what makes you think you would last being married?What is my move with this girl? Do I give up?
It has nothing to do with you. She loves you. She's got some deeply imbedded abuse issues that she has to work on. Let her work them out.