Translation:Kateřina, how did you learn that he had already been married three times?
Not sure what you are referring to. The translation above is using HAD BEEN
dozvědět uses the reflexive : už jsi se = už ses
jak jsi se = jak ses
"Kateřino, jak ses dozvěděla, že byl už třikrát ženatý?" - It's definitely right.
"Kateřina, how did you learn that he was already married three times?" (Reported) Sorry, but I need to know if this is really a bad use of the past tense. I still have a little mess in that.