What reason does Stella have for abandoning Blanche? Is it justifiable? Explain

Stella is torn between her husband and her sister, and she is very aware of the decision she has to make. If she believes that Stanley raped Blanche, then she would have to leave Stanley. If she believes that Blanche is crazy, then she has to send Blanche away. Stella seems to know, deep down, that Blanche was telling the truth. But it is finally Stella who is forced to choose magic over realism, shadow over light – desire over cemeteries. She chooses Stanley.

The last part of your question calls for your opinion.