Wow thanks for the replies all. Very insightful. In fact I do realize a lot of this is my "stuff" and insecurity is a huge waste of time. Allowing for the idea of sex with other people is a risk, but it's brought benefits already without having been acted on yet. In the week or so since this came out into our relationship, I've actually gotten more confident, and our sex has been more frequent and mind blowing quality, I should add. I've become more responsible for my life and issues, and our relationship has seemed to only grow closer.
About the tantra stuff, I don't know, I def am into the same kinda spiritual road he is in. (That's a looong, other story!
) I think at the time he said the stuff about doing it with her, we'd let the "spark" or whatever lapse from our relationship. We had gotten lazy, especially me, I confess. His being honest about his attraction instead of hiding or lying has done more for our relationship than a lot of other efforts. It's brought out things that went unspoken because we'd gotten too busy, other excuses, etc. Needs which were unmet and thoughts that hadn't been formulated much less expressed. Things have gotten better in many ways.
Again thanks, and any other thoughts or advice are gratefully welcomed!!