She must feel like she is fighting for his heart, and her being so stubborn, gets some sort of emotional high from that.
Yes, yes, yes to the addiction, and yes, yes, yes to it being bad. She's stubborn and her pride is involved, too. For him to have cut her off means you win. And that's just not gonna do, no way, no how. OM was her "better option" but suddenly she's not his and dammit she wants to win this as much for the sake of winning as anything else. That it also means that she "won" the OM from you is just a bonus.
In other words, very little about this particular OM and all about the addiction.
