okay....let me give this one a shot!
if you are still legally married, then you have NOTHING stopping you from relocating back to Boston with your children.
BUT.........
If he is determined to stop you from relocating, then there are things that he can do. The first would be to take you to court for a divorce and to establish custody and visitation. He can do this, the day that you leave. If he filed in new york, then new york will have jurisdiction and all hearings will be in that state. You can also file when you relocate (if he doesn't first), but most states require a 6 month residency to be able to do so.
He can request custody, he can also request that you not be allowed to relocate. if you already have, the judge can make you move back or you give up your kids.
there are a couple of things that you have going for you, and that is that your family is there and that the kids aren't in school.
you best interests would be to stay there (if the divorce is going to happen) and to get the custody and visitation schedule established. let the judge know from the beginning that you intend to relocate back to Boston (this will save on a new hearing later down the road, clear it all up at one time). be able to show that you are returning to your family, the type of lifestyle and environment that the children will be growing up in. have an established visitation schedule that allows their father plenty of time and be lenient on additional time that he may requests.
any records of his alcoholism? treatments? DWI's? anything on paper for proof that he has an alcohol problem? of course, he is clean now and shows that he is trying to improve. as long as he has that going for him, the past is just that - the past.
hate to be the doom and gloom, but i am going through a relocation now and this is all stuff that i was not aware of at the time. so i wanted you to know before you just up and take off.
good luck!
ambr