My theory is this...She had very low self esteem, was deep in her ED, and didn’t think she was good enough. She seemed quite naive, and had limited experience with boys, or hadn’t been treated very well previously. Jonny came along, with his bullshit “I’m in a boy band, Do you want to be in my music video” crap, and she was taken in by this. Then she got promised a life of luxary “on screen” and she went along with it. Then she got so far, and couldn’t get out, so just kept going... I’m not at all saying she’s blameless in this relationship as I think she also took advantage of the fact she knew deep down that Jonny wouldn’t look elsewhere, and the idea of him liking her more than her liking him, gave her some kind of power trip. Fast forward 11 years and they are likely both unhappy and resent each other, but also know if they spilt, they’d actually have to work