Success with IUI and low sperm count

Has anyone had success with an IUI and a low sperm count? My husband's count is 600,000. 😞 We were told today by a fertility nurse that we wouldn't be candidates for IUI if his count wasn't at minimum 3 million. We are through Kaiser Permanente and they don't offer IVF so we are literally looking at out of pocket for that. Has anyone else heard of not even doing IUI if sperm count is under 3 million? Should we be more aggressive with our request for one? Feeling pretty deflated this evening...