Ladies, would you be more offended if he leaves an LTR for someone else, or no one else?

This is an odd question, and something directed towards women, but if there's any guys here who have experienced anything like this, I'm all ears. This question was the result of a talk with some friends at a bar.

Suppose a couple has been in a LTR, and he tells her he wants to end it. The first question out her mouth could likely be "who is she?" (when an LTR is going badly, women usually have another branch ready to swing to, and because of projection, they may think we guys do too)

What if the guy says "there is no one else, I just want this to end, I'll find someone else whenever"

Is she more offended when she realizes that he's leaving her for no one? Or would she be more offended if he admitted that there's some one else he's interested in?