Could Yankee and lover of "well-toned, muscular" women, A-Rod, be the cause of the alleged marital problems between Madonna and Guy Ritchie? Radar reports that the issue of OK! Magazine hitting newsstands tomorrow claims the two are having an affair. The pair did go to the same gym last year and share a manager, after all; further proof in the article, Radar assumes, will be given through various "close friends."