What's the reason why woman manipulate men, or they try to manipulate men?.?

My relationship just came to an end, because of a disagreement, this time I decided to stand for what I thought was correct, without giving an inch, and things weren't done her way. Since things were done her way 100%, I decided to come up with a negotiation, where her and I were satisfied. Last weekend she wanted so badly for us to go to another city for the weekend, knowing was a weekend that for me make free time, was not going to be easy, I was way too busy, I suggested to do it on another day, and do something in town, she tried to change my mind, she couldn't, things started to go downhill, I let them go downhill!!!!. I did wrong on what is save the relationship, but I did right to not to let someone manipulate me. What are the natural/pschological reasons why a woman would do this to a man, who is not manipulative, but doesn't like to be manipulated?