oh man, I'm in a similar position.
I've been praying to God to will that I forget the past. I pray and say that in the flesh, I'll just keep looking back, psychobabbling everything, trying to find a way out while also rehashing...so, I need God to intervene directly, cuz I'm not really capable of not looking back.
And....
Well, the past couple days, I've been waking up w/o voices in my head from the past. I'm supposed "Bipolar I"...I think I'm just moody and people insisted on putting me through things, lol. Doesn't matter. I wake up calm, cool, and collected (and refreshed), and increasingly, the past doesn't haunt me as much.
Of course, its harder when your past involves a living, breathing person you've been involved with and care(d) for. That sort of thing...its hard. I wish I could say something, but...aside from some New Age divorce ceremonies or whatever, I don't think any human being has a really good, solid answer. I was a promiscuous sodomite as a teenager, which damaged me irreparably until Christ intervened. Anyway, I now pray on a fairly regular basis for God to break my connection/soul tie with everybody from my past. At first, I prayed just for the dudes I hooked up with, but now I pray to just break my connections to people from my past. God has plans for them, they matter as people, but I'm different and so are they, so...yeah, I pray to break that connection.