Translation:Because she remembered that she was married.
I can only comment on the English usages. "Because she remembered that she is married" means that she still is married. "Because she remembered that she was married" is also right, but carries an implication that she is no longer married. Or, it might be a phrase in a story which is entirely told in the past tense.
I (native AmE) completely agree that "was married" generally would mean that she is no longer married. But I would venture to say that, while both "is" and "was" are accepted on the English side, "was" is probably used more often and, in this case, it does not necessarily imply that she is no longer married. But the Czech sentence, as we see, takes a different approach with tenses in a sentence like this.
"Because she remembered that she is married." is already accepted.
"Because she remembered that she has been married." is not the right way to use the present perfect tense, I think. But it is the tense with which I struggle the most, so let's give others the oportunity to say something about that.
Because she remembered that she has been married can mean two things. I think they are both past perfect.
1 She has been married before. Meaning the state of being married. Might have been divorced/widowed since. I guess this would be like an all nominative, if you will
2 Someone, a priest or the like, has married her in the past. Again might have been divorced or widowed. This would have her being acted on like in an accusitive case, if you will
Ano, "Because she remembered that she is married." je akceptováno a asi vždy bylo. Není to učebnicová souslednost časová v nepřímé řeči (která chce "was"), ale bereme ten přítomný čas pro tvrzení s obecnější a delší platností.
Ale ten předpřítomný ne, ten se sem prostě nehodí. Ten se hodí do vět jako "I have been married for 20 years." "Jsem vdaná 20 let."