Hey, I remember you from my old days here at CAA. ^^
Accountability with the self-harm is definately a good thing, it's difficult, and the urges will probably be pretty strong for a while, but the longer you go without, the more likely it'll be that you'll not want to go back. I have dealt with salf-harm in my past, going back into four years ago now, and I've had the occassional slip up, but it's nothing near as bad as it used to be. I become triggered every couple of months now, where it used to be every couple of minutes/hours/days. It's a difficult fight, but every day away is another step towards becoming stronger. It'll get easier to handle in time, especially with having accountability for it!
As for the relationship thing, the first thing to come to mind is "Wait on God's timing!" Which it seems like you're starting to do with guarding your heart, or at least trying to. Trying is a good thing, and hopefully he'll come around to see your point of view. If he really cares about this relationship, I think he will.
I hope and pray all the best! If you need me for anything, feel free to shoot me a pm. I know what it's like to be recovering of self-harm, so maybe I can give some advice or something. Whatever, I'm here to chat if ya need me. ^__^