I may as well level. They stopped dating. She was heartbroken but their friendship repaired over time. So for the last 3-4 years they have interacted professionally and maintained some sort of friendship. I resented her for a log time because they denied that they cared for each other beyond professional interactions and "friendship" and then they immediately jumped in when we filed for divorce. But to credit her fairly, the two of them have been hands off the three or so years since. Only recently, when he and I decided to open up our marriage did the possibility of igniting something again come up. She is successful, kind, has a full life, and seemed a good fit. It just didn't pan out as expected.
I talked to husband after reading some of your responses. He says he respects my position. So I will have a convo with her as suggested above.
I appreciate you guys!