Well , the old cynic in me says that she was either told she was spoiling things for everyone and it was suggested she leave or she clocked the bad press she was getting and decided to leave herself , the children as a cover story. (because she's had ample opportunity to say she would be going back early to see them ).By the time she touches down at Santa Barbara I m sure this will have been reframed in her mind as , I was just so popular I was getting too much attention and I didn't want to detract from Harry and the athletes.
On reflection though , this is way too cynical and I think @LivelyMintViper 's scenario is the more likely.