Karin, only you can know what is best to do.
Your father doesn’t know about your husband’s true intentions; he only knows that life may be more difficult for you, especially financially, trying to make it on your own. I’m sure he doesn’t want bad things to happen to you financially, but your peace of mind is worth a lot more than an unhappy marriage to a coercive person.
If your Great Aunt is willing to lend you the money, AND you have arrangements to pay her back (even if it’s only $50 or $100 per month), AND your attorney has advised you of what you need to do to protect yourself, AND your husband and so-called “mutual friend” are still trying to coerce you into staying…
Well, I’m not you; I cannot say what you should do.
But if I were in a similar situation, I’d like to think that I’d get out, divorce, and request that the court withdraw my portion of the green card application. That would protect me legally from any future financial claims.
(BTW, I’ve left one emotionally abusive relationship, and one that almost became a physically abusive relationship. You can do it, too. You deserve to be treated better than that!)