Is marriage considered void if one is coerced into it and does not inwardly consent to it, and is it permissible in this case to seek a divorce and marry someone else?

It is not permissible to force a mature, sane girl to marry someone she does not desire. If she is coerced, she has the right to refer the matter to a judge to annul the contract. A marriage entered into under duress is valid if its conditions are met. The wife must sever her relationship with the other young man because it is Islamically forbidden and violates the rights of the husband and the rights of Allah. It is not permissible for her to marry this young man while she is already married. She must maintain the legitimate relationship with her husband. Requesting a divorce without a valid Islamic excuse is forbidden, but if she is unable to fulfill her husband's rights due to her dislike of him, she may request a khul' (a form of divorce initiated by the wife).