What happened in the end?

From the look on her face in the cab, it kinda looked like she would have told him to go. I don't think she invited him up. I think they separated afterwards but then she probably broke up with her boyfriend/fiance and him as well. They were still friends on facebook so I'm sure they reconnected somehow.

They cheated on their respective significant others because they're both that kind of impulsive, live in the moment type. That much was clear.