Dex is on his own side, but he had her ear, and for now, without the queen, he has nothing. If he loses her favor, he loses all of his power.
Another thing people saying it is not ntr if Megan was a guy this would have the tag. just because it was a girl and feels like a cheap setup to a threesome. she was his Fiancé and she was/is a li who did it for a lover and (humiliated/angered) the mc that is a lot like the definition of Ntr. when the dev said no ntr
When you are fucking around with both of them, no, it doesn't fit the definition. Your concubines fucking each other is not NTR ...not even if they love each other, and even if they did more than kiss since you met, which we don't actually know.
And like I said before, based on the timing, it was you doing the cucking, not the other way around. They were cheating on each other, with you, not the other way around.
Someone having sex before you meet them, is not them cheating on you.
Yes, Taina betrayed us, in a number of ways, but not like that.
And we also need to remind that Taina would be nothing more than her uncle's puppet if the MC hadn't have helped her to overthrow him. And what she does to repay the MC? ...she tries use to him as puppet just like her uncle did to her! ungrateful little bitch!
Her PLAN was to use him as a puppet for a bit and kill him, but she never actually did that. She changed the plan as soon as she got to know you (or maybe she just found she wasn't able to kill anyone, didn't have the stomach for it, depending on if you were an asshole or nice, lol).