I recently read this article on Huffington Post by Dr. Gail Gross about good reasons for divorce and when you know it is time to end your marriage.  She has now followed up with a powerful article how to make it a bad marriage a better divorce.  I highly agree with the information regarding children and how not to engage them as the adults and the adults should behave as adults. 

When a marriage with children ends, the parents are emotional and often angry. Expressing that anger by speaking ill of the other parent will damage your children and their relationship with the other parent. When seperating, using a child a leverage or destroying the bonds of the parental relationship can do lasting harm. Children would rather have two happy parents apart than live in the middle of a miserable or dangerous relationship.  Do all you can to avoid high conflict and love your children more than you hate your ex.