Oh boy! Sloan, I'm guessing you're about 20 as you say you're in college. In your twenties emotions can be very volatile and you haven't had enough time to learn how to manage them. You're still coming out of adolescence and this is your first big, serious relationship. So, there's no surprises there if you feel a bit 'hysterical'. That's perfectly OK. First of all - just breathe! There. That feels better doesn't it? OK.
"I love her, no we don’t have the healthiest relationship. I love her and she still loves me. Though she never says it anymore, and has not said that she thinks I will get me back in a very long time. I want her back, I’d kill to be with her I’d die for her. I’m planning to ask her to marry me despite out situation. Because I know my window of time with her is closing. What can I do to get her back? How stupid is me asking her to marry me? (I am asking her properly with a ring, her boyfriend did the same months ago, just asked out of the blue…) What should I do?"
Yes. You have made a bit of a mess of things up to now mainly be being erratic and over-reacting to everything. Look at this from her perspective for a minute. First you say you love her, then you say you just want to be 'friends with benefits' then you don't tell her you love her and break up with her... No wonder she keeps going back to the other chap because he at least is probably just being a bit more consistent, even if it's you she really cares about deep down, or even if she's just not sure yet but is trying to make up her mind. You are not helping things by being so dramatic and having Facebook battles.
"They still fight a lot, very recently over me in which he punched her and slapped her. He has also been verbally abusive. Today she was pissed at me as I had told her that I wouldn’t text her at all, or post to facebook. So I created a fake facebook profile to talk to her. We fought today as I had posted a bunch of stuff about loving her, missing her, and wishing to hear from her. Her boyfriend somehow figured out that the fake profile was mine."
Just stop doing things for a bit. Do as she asks and stop putting stuff on Facebook, texting etc. It's obviously only adding to her distress and confusion not to mention creating a complete crisis with her boyfriend getting jealous and starting lots of fights! This will only end in tears if it keeps up. Just knock it off for a bit? Your job is to make her life better, not worse. Take a chill pill. Breathe.
Her new boyfriend sounds like a total creep and if she's got any sense at all she'll get out of there as quickly as she can. Nobody should tolerate verbal or physical abuse for a single day. However, where has she got to go? You say her parents kicked her out. Does she have a safe place she could go to? Could you become an asset in her life instead of a liability? Might she stay with your parents or in some other way you could quietly now (without telling her) make some enquiries? Might you go and visit her parents and see if you could smoothe things out with them. Explain the situation she's got into and maybe help them mend their fences? You could be her knight in shining armour instead of the crazy dude who keeps tormenting her on Facebook.
Under no circumstances should you propose marriage just at the moment. If things work out with you guys, if she leaves the current guy (hopefully she's a sensible and smart girl and she will work that out for herself), then if your friendship is still intact, you might be able to work things out. If you do all that and can stay together for a year without any drama, then and only then would the subject of considering getting engaged or something be even hinted at. If it's a good idea to get married this year, it'll still be a good idea next year.
Hope that helps. Good luck and best wishes. Curious to hear how you get on.
"The only thing to do with good advice is to pass it on. It is never any use to oneself." - Oscar Wilde