Due to a romance bug, I was able to get lucky…
So I somehow managed to romance Gale and Astarion at the same time and I have no idea how. I was sort of romancing them both but was mainly focusing on Astarion and waiting for Gale to tell me “hey lose the pale elf, then we can be together†in which I was planning on dumping him for Astarion….
Only it never happened. So I just rolled with it. Astarion seemed to take priority over Gale, as I mainly travelled with him in my party but my Tav was technically in a romance with both of them. Then Haslin came out of nowhere and asked if he could join the party. He told me to ask Gale. But Astarion’s dialogue options also showed up and I knew he was okay with me “exploring nature’s gifts†the daddy bear. So I only talked to him and asked for his permission. Not Gale. I was able to romance Haslin as well.
I also somehow magically got both Gale and Astarions romance ending scenes to play back to back. I only have some cosmetic mods, nothing that allows a foursome so mission accomplished I guess?