Translation:My wife does not know why she married a Czech guy.
Why is the "za" in this sentence? I thought that "vzít si" takes the accusative without a preposition.
Vzít si is basically a shortening of vzít si za muže/manžela (or even za ženu/manželku)
So it's either Moje žena neví, proč si vzala Čecha. or Moje žena neví, proč si vzala za muže/manžela Čecha.
“Za” in this sentence is the rough equivalent of the English as or for. A more literal translation is “…took (herself) a Czech guy for a man.” So “za” does not depend on “vz si” but is necessary to accompany “muže;” you could omit “za muže” but not “muže” alone.
"My wife doesn't know why she married a Czech man" Isn't "man" just as acceptable as "guy"?