[Gale can be quite easy to read when Astarion takes the time, it's true. Here, in the privacy of his tent, he finally has more than a moment to do so. That's how he knows Gale is being genuine. Even though he doesn't know quite how to respond with his own heart twisted out of shape and suddenly too heavy in his chest.]

You won't lose me, not that easily. But, by the hells...don't leave me without you instead. I want you at my side, Gale. For all the sunrises and kisses and times to remind you that you're worthy of it. Don't you understand that?

[There's a waver to his voice that he doesn't bother to hide. He needs Gale to know how important this is, how much he matters.]