This 👏 is what 👏 I've been saying.
There is NO WAY Gale and Mystra did the deed in the flesh.
Okay, so I was willing to take this at face value-
"We enjoyed each other's company- body, mind, and soul. But even so, I desired more."
But then later in the Gauntlet of Shar, he said this-
"It's true, for a time, I neglected the physical in favour of celestial euphoria. But our relationship was no less real for it."
And this is after Gale had already spoken to Elminster and received Mystra's directive to use the orb. He's had time by now to not only marinate in that, but also, he's starting to see just how imbalanced their dynamic was.
And that's important - because as he becomes more disillusioned with it, he also becomes more truthful with both himself and you about the nature of their union. He's taken off the rose-colored glasses so that by the time we actually get to see them interact face to face, it becomes very clear that Gale's experience was not Mystra's. (I've already gone over that, so I won't revisit it in this post.)
The second romantic cutscene (the astral scene) that triggers after you've visited Moonrise the first time, Gale offers this:
"I want it to be perfect - to bond with you in the way that gods do- intertwining our spirits in visions of the Weave."
Aside from it being his go to, even if you tell him that he's enough without the theatrics, Gale very fervently tries to convince you that this way of joining is superior. Furthermore, it seems that being with Her like this for so long has in many ways turned him off of physical, fleshy, human delights.
He speaks of it almost like it's beneath him. Until, of course, you quite literally ground him back to Earth-
And, yeah, maybe it's just a line, but remember time also moves differently in the Astral Plane. While he could have been in a sexual relationship with Mystra for four years at most (1487-1490DR)- because before that, she was only at a fraction of her power and could not inhabit a form at all, to my understanding, plus his isolation for a year after she cast him off before he was abducted by the Nautiloid- we have no idea how long four years is in Elysium. But long enough that Gale seemed to think of it as home for a time (this is a bit of conjecture on my part, purely by the way he references/describes Mystra's realm in various dialogues.)
Now, again- not debating the legitimacy of the relationship at all. I agree with a lot of Gale's assessments when it comes to connecting spiritually on a higher plane of consciousness. The only problem being that while Gale could indeed see that plane, he wasn't actually a part of it. Half of his personal quest is in Gale coming to the understanding that he and Mystra are not equals. Kafka would have a fucking field day with him.
It's another one of those unfortunate instances where I would die to have a conversation with someone just to pick their brain for a while, only for them to be fictional.