Is it permissible to separate due to not having children, and does the husband's belief that his wife knew about her incomplete pregnancy before marriage affect this?

If a man is afflicted with a wife who cannot conceive, he should keep her under his marital bond if she is religious and of good character, and marry another woman seeking offspring, as the Prophet, peace and blessings be upon him, said: "Marry the fertile, the affectionate." If the wife knows before marriage that her pregnancy will not be complete, it is not permissible to conceal this, because infertility is one of the most significant defects affecting marriage.