Why would I be obligated to stay with you?

[Sentimentality? Ridiculous. If Rae Sloane showed up and tried to get in his way, he'd have her killed too.]

If my feelings disappeared, I wouldn't have hesitated leaving you. And most likely killing you in the process. [He'll just casually throw that out there because well, Kylo wouldn't be surprised anyway. The man may be reckless, but he's not stupid.]