I've been trying to improve on Dzug's answer. However, experience should have taught me that this is pointless. (Dzug is AnswerBank's 'superstar'). I've come to the conclusion that he's right: One of you should get a new job (or a new partner!).
For what it's worth, my suggestion would be that you should consider somewhere at the eastern end of the Jubilee line. (i.e. Canning Town, West Ham or Stratford). Your boyfriend would have easy access to the M11 for the drive to Cambridge. You'd have a fast tube service to Waterloo, for the train to Ascot.
Chris