we know 'characterless' is not just about having a physical affair but our indian law describes adultery strictly in physical sense.
So you should focus on cruelty factor - desertion, not interested in marital obligations, intentionally hurting you by flirting with other guys, disussing your family personal issues with her 'boy' friends, spending more time with other guys than you all these are not adultery but will build your cruelty case. Your advocate should take the 'ideal indian family' (which is common to all religions in our society) as a reference and show how much she has deviated and hurt your sentiments.
I dont feel that only SC should set a precedent to every cruelty type - a strong advocate can argue and set new precedents at the lower family court itself.
First gather conclusive evidence (her interactions with multiple guys not just one odd guy, preferably WRITTEN like SMS< facebook comments etc. etc.) or take photos/videos of her getting close to other guys - it can't be adultery but it can be cruelty. (Compare: improper touching by a guy is s*xual harassment, so improper advances by a girls should be cruelty to the husband, not to that lucky guy :))
and then file for D under cruelty grounds. You do have grounds to build your case, so first build it. and as any one else, be ready for the return gift of 498a.
Many lawyers would be reluctant to take day to day events (like not cooking, flirting etc.) on cruelty grounds as they are not confident of proving it in court.
Ultimately it is your advocate who should translate your events into cruelty and convince the judge.
OR ELSE , if you are lazy and dont want to move, just relax, wait and watch, dont be in a hurry for D, let her blink first. live your life, find a new partner and wait for your wife to file cases/Divorce etc. Such girls are so adamant and insecure they dont care for reasoning, you are beaten from all sides. your only option is to go down and THEN get up.
Enjoy your life.