Do not blame yourself. It isn't about you. It is about his pathological need for total control.

Do your mutual friends know the truth about how he treats you? If not, what would they say if they knew?

I think you have been given quite an accurate taste of what life will be like if you marry him. Is the way he treats you what you want? He isn't going to change. In fact, usually an abuser gets worse after marriage.

There are very many red flags surrounding him, dangerous ones, which you are aware of, they are why you came here.

Your children will not be allowed to meet their grandparents ever because he doesn't approve of how your education is being financed? Seriously?

You asked what you should do.

If you were my daughter I would want you to listen to that internal voice that tells you to fear him.

I would want you to break up with him at once and totally block him and avoid Boston for your residency.

And I would want you to call the Police if he came anywhere near you after you blocked him.