Return of the ex gf, options, opinions all are welcome.?

ok so messy break up months ago. I told her how much I loved her and was as sweet as sugar (we were friends first and i just fell in love with her over a year or so), was helping her move to a new apartment and tipped her garbage can accidentally exposing a condom wrapper, not mine. We were dating until about a week before so I was upset of course. I ws speechless and left after I had finished moving her to her new place...I didn't mention what I had seen as i was heartbroken you can imagine. I did mention to her what i had seen later that night over the phone when she asked why i was so quite and cold all of a sudden and why i didn't stay or say goodbye when i left. We didn't talk for a a week or so and then i broke the silence and (******* stupidly) wrote her a letter about how i felt and that i still wanted her in my life. (she had said in that phone conversation when i confronted her that it was just an "arrangement" with someone else and that it meant nothing...I didn't care, and still can't see how she thinks that justified it). when i gave her then letter is was shockingly in the middle of what was one of her dates with some new guy, they both came to the door and i handed her the letter, of course shocked again at the predicament i was in...i am a rather large fellow 6 foot 5 235 and muscular as hell, but i am teddy bear and would never hurt anyone...anyways this new guy didn't know that and tried to hit me, breaking his own arm in the process. I left, she email how i was crazy and that it was a terrible idea to come there etc. finishing off with "thanks for being my friend". No word from her or myself in months, like 7....now a facebook message from her "I miss you, I miss hanging out with you and your friendship. I just wanted you to know that". What does she expect from me? what the hell is she thinking? What am i supposed to do with that? After finally getting over it, she decided she wants to talk to me or tell me something? Who does she think she is? PArt of me wants to write something but i know she is s and i hate her. I really don;t know what to do so go nuts and let's hear from all sides of the spectrum!