My Super Ex-Girlfriend (2006)

When Matt Saunders meets Jenny Johnson, he thinks he's found the perfect girl. However, he decides to break things off with her when she becomes too needy, controlling, and jealous. Jenny doesn't take it well and decides to get back at him by using her superpowers, as it turns out Jenny is a superhero named G-Girl. Meanwhile, Matt and his co-worker, Hannah start to have a romance with each other which sends Jenny over the edge.