Those of us on the hub who know your DW were completely shocked to hear of this situation - so I can't even imagine how hard it was for her.
She is amazing and I think you are very very very very lucky that she is prepared to engage in any sort of friendship with you given everything that has happened. I am not saying you are a bad person or anything, but I imagine if I was in that situation it would be so bl00dy hard to let you in.
I have no advice though - the decision is with her.
As for joining/posting on BH - if it was my ex I would appreciate if they contact me and made sure I was ok with it. If I wasn't I would appreciate they leave.
Good luck - I really hope you can work it out.