Question: What was the show called that featured a teacher going out with an actress? The theme song was Joe Jackson's "Is She Really Going Out with Him?"
Answer: Actually, to be a nitpicker (which is, after all, what I do), it was Sugar Ray's rendition of Mr. Jackson's far-superior version of that song.
Anyhow, you're thinking of the short-lived I'm with Her, which debuted on ABC in September 2003. Based on creator Chris Henchy's relationship with real-life wife Brooke Shields, it focused on a high-school teacher (David Sutcliffe) who finds himself romantically involved with a star (Teri Polo) and the zany complications such a situation brought about. Problem was, he wasn't with her for long. The show was gone the following April.