Its about priorities and responsibility, or the lack of it (in divorce cases)
Prioritizing the marriage often occurs at the beginning but gradually changes.. maybe cuz of work or some factors.. thats when problem arises.
oftentimes, as the priorities change, the level of responsibility follows suit.

having a career for both husband and wife is not the problem, IMHO, its HOW you handle your marriage and your career. what is more important? what should you give more time to? who should step down if something happens?