Dear User
In response to your query No.1,
Yes you are entitled to file application for Divorce. You need to prove your allegations beyond reasonable doubt with substantial proofs.
In response to your query No.2 to 4, You need to prove your point i.e, Adultery. There are various parameters viz., your social status, community, your place of living, educational back ground etc., apart from others, which the court will take into consideration before awarding the maintenance.
Further, court will have a soft corner towards the claims made by your wife in her application, which you need to contest tooth & nail.
In order to reduce quantum of maintenance which you are likely to pay to your wife try and collect the below mentioned documents:
1. Any loan if you have, the EMI you are paying.
2. Obligations pertaining to maintenance of your parents.
3. Any & All overheads / expenditure you are paying with supporting documents.
4. All the payments / expenses to be made through Bank only.
PS: It is advisable to go for one time settlement i.e., by paying one lumpsum payment viz., PERMANENT ALIMONY.
Good Luck