The ending ruined it for me. She should have not taken him back. He had a chance to have the "I'm seeing other people" talk early on avoiding it having to be a all or nothing approach. His character isn't emotionally mature enough to have that conversation. His character would have probably gone with Nina #2 if the other Nina didn't take him back. So what if she wasn't into your book, she was upbeat and didn't make him go through a bunch of tests.