Ask questions and get specific feedback as to what he likes and doesn't like about your previous versions (get on a phone or video call with him, it might be easier). Then say that you'll do one more version, but after that, if he needs more work, it'll cost X amount for further versions.
In the future, specify up front how many revisions are included in your price and how much it'll cost for any additional versions. Then stick to that. Or, suggest that clients hire you on an hourly basis instead.
But every now and then, a client simply won't like your work no matter what you do, and you'll have to agree that it wasn't a "good fit" and suggest that they hire a different freelancer. It happens - can't win 'em all. Remain calm, polite and professional, and try not to take it personally.
