Zyrtec affected my mans libido

Okay so this is hella tmi probably but my bf and I have been having unprotected sex for 7 months (trying but not trying you know what I mean?) and I went to the gyno to get tested and see if I was the problem and turns out I’m perfectly healthy reproductive wise and he recommended my bf get tested and the doctor told him today that the thing affecting his libido and sperm count basically was his Zrytec allergy pills he takes every morning??? Like wtf? So he’s gonna stop taking them and we’re gonna see what happens next month!