Kelis and Nas on divorcing while pregnant

How bad can a marriage be that it would drive a wife who is seven months pregnant to file for divorce from her husband of six years? That is exactly what Hip Hop superstars http://www.divorcesaloon.com/how-to-divorce-a-rapper Nas & Kellis are going through right now.
The wife filed for divorce on the grounds of “irreconcilable differences.” How incredibly alienated and cold she must feel right now being pregnant and going through a divorce. They must have been very, very unhappy that she couldn’t even wait another 2 months. Have you gone through this? What is the rationale in a situation like this? What would push a woman to file for divorce at a time like this?