Does the second wife bear the burden of the problems between the husband and his first wife because of her marriage? Is the anger of the husband's mother towards her because of this marriage considered valid? Is the husband's refusal to divorce her, if it causes his mother's anger, considered an act of disobedience?

If the marital problems occurred because of the marriage to this man, then there is no sin upon either of you. The husband's disobedience to his mother regarding his marriage to you or his refusal to divorce you is not considered an act of undutifulness ( 'uquq ) if her command has no legitimate شرعي basis. The Shari'ah has forbidden a wife from seeking the divorce of her sister so that she may monopolize the good of her husband for herself alone.