I’ll let James Martin explain:
Also, before I talk about the reasons scholars believe that he was almost certainly single, I should point out that the manuscript in question was written long after the canonical Gospels (Matthew, Mark, Luke and John) were written. The fragment is most likely from the fourth to the eighth century. By contrast, the earliest Gospel, Mark, was written in AD 75, only 40 years after Jesus’s time on earth. The fragment in question, at its earliest, was written three hundred years after the canonical Gospels. In general, it’s better to rely on sources closer to the actual events, particularly, as in the case of Mark, when there were people still alive who had known Jesus, and could presumably have corrected any inaccuracies in Mark’s text. Three hundred years later, people take many more liberties with he story.