Feel free to add to the list.
http://www.cnn.com/2014/10/15/opinion/schwartz-single-women/index.html?hpt=hp_t3
1. A useless husband
If a woman is poor and only meets equally poor or poorer men, she's in a tough spot. It is no secret that many women do not choose to marry if the available partners will make their economic situation worse.
2. Success changes everything
When a woman is very privileged or highly successful, marriage could come very easily -- or not. Moreover, a woman doesn't need a husband who is a high-powered corporate attorney if she is a high-powered corporate attorney.
3. Unwilling to make traditional compromises
A woman who doesn't want to settle for cooking and cleaning and being the primary parent that society prefers. She is not meeting guys who want the kind of woman she is.
4. The marriage penalty tax
Some women are in an income bracket where marriage inflicts economic costs.
5. Avoiding cheating men
The three women all said they didn't want to marry because "the men of our class will all expect to have mistresses, and it is better not to marry than have to put up with that."
6. Waiting for the "one"
These women wait for the perfect guy, or the guy who they would fall in love with and love them back just as much. If that man doesn't come along, they prefer to go alone. As women get pickier, more factors enter into the marriage equation.
http://www.cnn.com/2014/10/15/opinion/schwartz-single-women/index.html?hpt=hp_t3