Is it permissible to divorce a wife who has been raped and is pregnant from the rape, and to whom is the child attributed, and is it permissible to have marital relations with her, given the husband's desire to conceal her situation and the presence of other children?

Do not divorce your wife because she was coerced into adultery, and warn her about the prohibition of suicide.

The child belongs to the bed, and the default is that the pregnancy is attributed to you, as long as the marriage is valid.

If you are certain that the pregnancy is not from you, then deny it, and separate from your wife until she delivers her child. You will then be required to accuse her of adultery and disown the child's lineage from her.