adultery with a widow

After 24yrs of married life my husband has developed adultery with a widow lady. He is working in a state govt undertaking organization & he was transferred to other district on deputation where he is right royally living together with that widow lady and her two daughters. We came to know about this through a letter sent to us by localites in Jan'11. From that time till date he stopped coming home and completely avoided all communications with us. We have 26yrs old daughter and he neither call or meet her. He dint attend his only daughter's wedding also. He is completely avoided by all relatives and friends. I tried launching many complaints through written letters, online mode right from CM cell, his MD, chairman, SP, Commissioner etc...he was avoiding all my complaints by some lies on me and applied divorce on me. Three times divorce case got dismissed due to absense of my husband. That lady has filed deferment on me but not at all appearing to district court but not at all appearing to court. Both of them have filed these cases as a protecting shied for continuing their adultery. His office has not transferred him or taken any action of him inspite of my repeated complaints. They are doing wrong and i am paying for their mistakes without anything wrong from my end. My lawyer says filing adultery is of no use as it is very difficult to prove adultery. I have locked her house at 3 am and took video of him inside her house. I am down with depression and I need justice. Kindly guide me what sort of action to be taken on my husband to prove his adultery and avoid me getting divorce.