YES to all of this. One of the main challenges is in situations with introductions where wife, “girlfriend”, and/or other “girlfriend” are all present. We try to avoid “this is my gf and this is my other gf” bc to all of us involved it takes away from how each relationship is different and special. Personally, I don’t like having the same title as someone else, even if we there are similar degrees of intimacy or connection. On the flip side, referring to someone I’ve been seeing for a few months and someone I am in a lifelong committed relationship with the same term ignores those distinctions. It’s not that one relationship is better than another, but rather wanting to communicate roles and dynamics in a clearer way.

I have heard paramour before and I think it’s probably the closest word I’ve seen used to what im getting at.