Everyone is related to everyone, some how. I don't think it matters unless you can draw a straight line from one person to another.
My fathers great grandmother was a Pratt. If you go back a few more generations, to 1863, the family's last name was Welles. From 1863 go straight back to 1487 in the Wells family. John Welles married Cicely Plantagenet, daughter of Edward IV of England.
That is a pretty straight line from me to the King of England. No fourth cousin, twice removed, on my mothers side nonsense.
Try to explain how your cousins wife's cousins are related to your kids. Their not, really. Once you go beyond your cousin, the next generation is your second cousin, and if it's your cousins wife's family, is that once removed ? I don't know. I think I'll stick with not related.