Get a job and stop depending on your ex for payments. There are a lot of single mothers out there that work hard and take care of their kids without help from others.
I think the person is trying to get started in her career. Also, if you are a single parent, you'll quickly notice that being a parent doesn't give you the necessary freedom to take as many risks and do whatever the hell you want at any instance of time. I'm sure it's not an easy task, especially if you are dedicated to being a good parent.