Don’t we all want someone we can rely on? Of course she wants to settle down, ultimately.She's an open-minded, promiscuous girl but she ultimately wants a good guy who will treat her nice and that she can one day settle down with.
Taylor can be that guy and she knows it. She clearly loves him but is either too scared or too proud to admit it.
If I understand this story right, it is not completely separated from reality. That means that Tales and Nikki can fool around, for the purpose of the story, but they can’t start a serious relationship.
But, as I read it, they will always be together in some sort of way, because they are twins.
Molly could be Tales’ girl and be OK with Nikki being who she is. But we don’t know much about Marc. It seems unlikely that he would be OK with Nikki being close to Tales.
If Marc was important for the story, why haven’t we seen him? Therefore my guess is that Marc is not to stay.