This would be inconsequential except for two very important things:
- It was written down.
- Islam's most revered book (the Koran) says no less than 91 times that Muhammad is the ideal example of conduct for Muslims.
Unfortunately, the problem isn't confined to marriage. Muhammad serves as a model of conduct in other ways. He ordered non-Muslims assassinated for criticizing Islam, he aggressively conquered non-Muslims through war, he tortured, he raped, he owned slaves, and much more. And his example has been preserved in writing for all time.
This article has been also posted here on Inquiry Into Islam and here on Foundation for Coexistence, so you can share it with any friends or relatives of yours who might find this to be inflammatory — they might be more inclined to read it coming from a site without "warrior" in the name.