1. On the basis of the recording in your possession you stand a very good chance to get divorce. If her infidelity is established she will lose the right to claim maintenance. A wife who commits adultery is not entitled to claim maintenance/alimony. So contest her maintenance case fittingly on the basis of the proof in your possession.
2. Has she filed her reply to the divorce petition? If she does not come to attend the counselling the court will draw an adverse inference against her.
3. You ought to take bail in the dowry harassment case filed against you. A petition for quashing of the case, subject to the allegations in FIR and the legal advice received, may also be filed.
4. You can also file a criminal case for adultery against your wife's paramour(her uncle). If held guilty he can be imprisoned for up to 5 years.
5. However, no case of cheating is made out in the given scenario. The legal concept of ''cheating'' is at variance from the meaning assigned to it in ordinary parlance. So no case of cheating, much less against your father-in-law, would stand on its legs in the court.