A man cannot marry his wife’s sister while his wife is still alive. Can he marry his wife’s sister if he divorces his wife?
No. A man’s wife’s sister (his sister-in-law through his wife) remains forbidden even after he divorces his wife, and is only permitted after his wife’s death.
This is derived by the Talmud (Yevamos 8b) from the word “bechayeha,” in her lifetime.