You sound like you're in a good place, D. I would advise you to not have anymore of these outings. Especially now that you know, whatever the circumstance may be, that she is still somewhat involved with OM.
I hope you will distance yourself from her but still maintain a good co parenting relationship. I'm not quite sure what that looks like entirely but I do still think your W has no fear of really losing you. My suggestion is to cut her off as anything more than a coparenting relationship.
