I had this discussion with a friend of mine a while back. The husband is required to support his wife. If she wants to forgo that support, she’s allowed to.
It would make a difference if she changes her mind. If we’d write that she’ll support him, it’s too bad – she accepted that she’d be providing the support.
If we continue to write that he provides the support, and she allows him to learn in kollel, she can change her mind. If he refuses to go work and support her, she can go to Beis Din and demand that her husband fulfill his terms in the kesubah. If he still refuses, she can demand a divorce.