what is considered grouse misconduct....

I live in Massachusetts. We are scheduled to return for trial in our divorce in August because we could not come to a settlement agreement at pretrial.
Here is the what has happened. Husband left marriage. Had a girlfriend and now lives with her. Denies although I caught him with her many times. He is an alcoholic. Court ordered to be evaluated but doctor says he has no problem!! I do not have the money to push the issue any further. Physical abuse while we lived together and also after he moved out. I finally got a restaining order after last episode in front of children. He was arrested, pleaded guilty, is on probation. His behavior for the last 4 years of marriage, drinking, drugs, 3 girl friends as I find out now, gambling.
Husband wants 50/50 split of marital assets. Only asset is the house. We bought the house 3 years ago, no down payment, I have payed the mortgage for the last year. There is at this time almost $60,000.00 in equity. He wants half with 6% a year for the next 19 years. I refused to give in. Judge says he will hear evidence but I need to prove total grouse misconduct in order to have him give my husband less. We live in a no fault state. I solely cared for the children during the marriage. I have a babysitter who will testify that he never returned from work each day leaving her with my kids until I got home. I have cancelled checks paying off the bookie. There are court records and police records for the abuse along with a (still) broken front door from one of his episodes.
Our kids have never been around this women he is with and it has now been a year since I told him to leave. He says he is going to force his kids to meet her. My son has told his father that he wants nothing to do with her and doesn't want to go to their house. My son (age 9) witnessed arguements and the abuse in our marriage because this women was the reason for out fighting. His father stupidly paraded around our small town with this women and then called my son a F------ Lair when he told his dad he saw him with her. He also days later told his son to look for him at a baseball game that was on T.V. and the seats were in the second row behind home plate and he was in view thru the entire game. My son was so upset because he took this women to the game. These things along with many other took place while he still lived at home.
I have no witnesses except for the babysitter because I can not find anyone else (although there are plenty of people who witnessed all this behavior) who is willing to get involved.
I can't figure out a way to pull all this together to have a case against him. It is killing me to think I will continue to pay this mortgage for the next 19 years and then have to sell the house and give him his share.
Does any of this look it might work for me? Again tonight on the phone he is laughing at me telling me the judge doesn't want to hear our dirty laundry and I better just settle.

Please any advice or feed back will help. All my laywers keeps telling me is that what is really going to work is if I can find someone who will testify about his drinking, drug use and this women all together. I do want to protect my kids from this situation/enviroment that he says he is going to force them into. Best interest for the children?????? Whar do I do?