The immigrant I sponcered is not mentally stable and has been abusive, am I required to support the immigrant due to the I-184?

I take it that you are referring to Form I-864 affidavit of support required to be signed by you when your husband applied for permanent residence through you. (There is no Form I-184 applicable to your situation). As your husband's sponsor, you were required to have an income at 125% of the poverty guidelines in order for his application to be approved (if you did not meet this requirement, there are other ways to meet this requirement).
Answers to your questions: 1) The Form I-864 does not require you to support your husband at 125% of the poverty level or make any kind of monthly or alimony payment to him. Rather, the Form I-864 requires you to be liable for reimbursing the U.S. government if your husband applies/obtains any type of welfare or means-tested public benefits, e.g. food stamps, SSI, . If your husband has $20,000 in a foreign bank account, he is probably uneligible for certain welfare benefits from the U.S. government. 2) True, you did not know how he would behave years later. But Form I-864 and its instructions do tell you that you are liable for a period of 10 years or 40 quarters (under social security laws) from the time that he becomes an immigrant, if he should apply/use any means-tested benefits, even if he is divorced from you unless he dies, leaves the country or becomes a U.S. citizen. 3) If he is already a U.S. citizen, then you don't have to reimburse the government for any welfare benefits that he receives. That's one solution if you want to avoid this type of liability. 4) If your husband is abusive, including physically abusive, or you need to separate or divorce him to protect yourself, you can apply for restraining orders against him from the family law court. The federal immigration laws make an immigrant (a permanent resident who is not a U.S. citizen) subject to removal proceedings if he or she is convicted of a domestic violence crime. Even if your husband is not convicted of a domestic violence crime but violates any restraining orders (from the family/civil law court), it would be conduct which could make him removable under that federal statute. Certain restraining orders can protect you from revealing your current whereabouts, in order to ensure your physical safety. Since restraining orders and divorces are usually a matter of state law, it is best that you consult with a Florida licensed family law attorney about restraining orders available to you in that jurisdiction.

I take it that you are referring to Form I-864 affidavit of support required to be signed by you when your husband applied for permanent residence through you. (There is no Form I-184 applicable to your situation). As your husband's sponsor, you were required to have an income at 125% of the poverty guidelines in order for his application to be approved (if you did not meet this requirement, there are other ways to meet this requirement).
Answers to your questions: 1) The Form I-864 does not require you to support your husband at 125% of the poverty level or make any kind of monthly or alimony payment to him. Rather, the Form I-864 requires you to be liable for reimbursing the U.S. government if your husband applies/obtains any type of welfare or means-tested public benefits, e.g. food stamps, SSI, . If your husband has $20,000 in a foreign bank account, he is probably uneligible for certain welfare benefits from the U.S. government. 2) True, you did not know how he would behave years later. But Form I-864 and its instructions do tell you that you are liable for a period of 10 years or 40 quarters (under social security laws) from the time that he becomes an immigrant, if he should apply/use any means-tested benefits, even if he is divorced from you unless he dies, leaves the country or becomes a U.S. citizen. 3) If he is already a U.S. citizen, then you don't have to reimburse the government for any welfare benefits that he receives. That's one solution if you want to avoid this type of liability. 4) If your husband is abusive, including physically abusive, or you need to separate or divorce him to protect yourself, you can apply for restraining orders against him from the family law court. The federal immigration laws make an immigrant (a permanent resident who is not a U.S. citizen) subject to removal proceedings if he or she is convicted of a domestic violence crime. Even if your husband is not convicted of a domestic violence crime but violates any restraining orders (from the family/civil law court), it would be conduct which could make him removable under that federal statute. Certain restraining orders can protect you from revealing your current whereabouts, in order to ensure your physical safety. Since restraining orders and divorces are usually a matter of state law, it is best that you consult with a Florida licensed family law attorney about restraining orders available to you in that jurisdiction.

ALERT:
In my view, your situation illustrates the flaws with the federal statute, Section 213A of the Immigration & Nationality Act, which purports to confer a right on the sponsored alien to sue his U.S. sponsor (on Form I-864) for support at 125 percent of the poverty guideline during the period of its enforceability.

There are many defenses you can raise to a claim for support obligations under Form I-864, including: 1) infringement on your marital rights (e.g. if there is a conflict between the federal statute and Florida divorce laws), 2) that it is legally void for lack of definite terms, 3) illusory contract, 4) duress, 5) unconscionability. You could even make a constitutional argument that it is an interference of your "FREEDOM TO MARRY" because Section 213A penalizes certain classes of U.S. sponsors such as yourself when it conferred a right to the sponsored immigrant to sue for support.

You should consult with a Florida licensed family law attorney and an experienced immigration attorney to deal with the above issues. Good luck!

[Note: The information provided is for consumer education purpose only, is not intended to be legal advice to be relied on, and does not create an attorney-client relationship].