Any case u/s 498A is a criminal case - a police case in which even in-laws are involved. Originally this section was added to stop severe harassment meted out to wives. But now it has been grossly misused. When the case u/s 498a is under proceeding and any other case is filed either criminal or civil, the same would be dieced on its merits separately. However, the litigant can take the support of points/documents raised and produced under any other related case. It is up to the court to weigh the value of the same in the case under its jurisdiction and power.
Divorce, although a civil case, can admit the evidence produced u/s 498A. Such evidence will be of great help in deciding the case. Mens ria or intention/motive will be decided based on such evidence. It may guide the court in arriving at a proper decision/order.
Extra-marital relations becomes a good ground for divorce in any religion. If marriage has taken place by playing fraud annulment of marriage can be decided by the court. However, solid proof and testimony of witnesses will be critical. Adultery is a solid ground for divorce and non-sanction of maintenance allowance. At the same time, however, it is difficult to prove adultery. You may please keep all these points in mind while proceeding with your litigation. Advice from a good family lawyer may help. I am practicing on family side.