Will our home have to be sold due to divorce? Custody? Grounds?

We have been married 15 years. He makes 90 k year, and we are in a shared home on property given to us by my family. Mortgage is high. We have a 4 year old and a 14 year old. I worked and made 28+K a year for 10 years, but stayed home to raise last child, and now changed fields and only make half that amount working part-time. He is moving out. He has large 401K- may retire at 62 and is now 57 years old. He had planned to pay our mortage off then (62), but obviously will not now. I am 37, years of verbal and emotional abuse, his alcohol abuse, controlling, no love left. What grounds do I have? WHo should file? Also have a seperate farm in only my name, my mother's home deeded to me at her death, and he has the same from his father. Do these factor in? Will he have to pay alimony? Will he have to continue paying for our home- approx. how much? Or put up to sell? Will things deeded solely to me or him come into pic.? Can my teenage son choose to move with him-change schools, etc. against my wishes? How is custody decided? He will want 14 year old, but leave youngest here, yet I fear that even as shared custody. Last year son drove him home, due to alcohol, twice! He has threatened to kill me on occasion, and I feel now that he has said will leave in 4 days, should let him go while there is peace. I don't want smear campaign, but do want health coverage and need big $ help. Do grounds make a difference in alimony decisions? He'll deny it all. I have no proof- only m