1. If he proposed divorce case is not on mutual consent and it shall be on the contested grounds, then you may plan to return to India and stay here for another two to three years, initiate the divorce proceedings, conduct it with your presence and return after the case is disposed OR
if you cannot spare time to conduct the divorce case in India which may run for years, you may file the divorce case in US itself since she had resided there with you for few months.
2. The alimony aspect will be taken care as per law in US whereas in India it shall be on the basis of how cleverly the parties manipulate the claim and repudiate the same. The documentary evidences and non-involvement of immovable properties are few disadvantages in her alimony claim if the divorce case is contested by her in India when compared to US divorce proceedings.
3. Since you hav already planned to divorce her seeking dissolution of yor marriage with her, there may not be any use or advantage for you to apply for green card for her.
In fact that may be hazardous to you and the disadvantages would be on the higher side, which you may analyse in your free time.
Her concern could be if we agree on MK that in the US and I leave for India then would she have any rights left or if she files in India and takes alimony in India she may not be able to suppprt herself in the US as she would need monthly money in dollars.
Do not make any commitments to her in a hasty move nor you should budge to her pressures or falling weak to any sentimental pressures or emotional blackmail on the pretext of visitation rights to your kids etc.
You should handle the situation cleverly.