I think your best bet at this point is to keep talking to her and taking baby steps. Find out what her comfort level is and stay at that point for a while. Move slowly. There isn't any rush. It took my husband and I about 5 years to get from the initial discussions of opening up our marriage to me having an outside relationship, and then another 2 years until he had an outside relationship. These things don't happen quickly, but it can be really fulfilling if you take your time, build trust and don't rush.
Everything will be ok in the end. If it's not ok it's not the end.