prohibition on Cohanim in choosing a wife

A question was given to you if Cohanim are prohibited from marrying a woman who has had prior relations with a non-Jew, which your answer was that in fact it’s true that a Cohan is prohibited from marrying a woman who has had prior relations with a non-Jew. But isn’t it in fact that Cohanim are prohibited from marrying any woman who has had ANY prior relations with any man if he is a Jew or a non-Jew both are not forbidden?

A Cohen can't marry a Zonah. The Halachic definition of such a woman is a lady who had relations with a man she can't Halachicly marry, a regular Jew would therefore not render her a Zonah. [Shulchan Aruch EH 6;8]