The most potent predictor of being happily married is being happy before you marry. Marriage does not make you happy, although the prospect of sharing life with a loved one can provide motivation to make yourself happy. What marriage certainly offers is someone on whom to blame your unhappiness.
Me 42, W 39, S8, S6, S2 M 11y, A & ILYBNILWY 11/08 Walking away from a bad situation.