I sponsored my then-wife, who is from Belgium, for a green card. We got divorced one year ago, which was about four years after I signed the Form I-864 Affidavit of Support. Both of us were working all that time, and she continues to work in the U.S., but her income is very low. So I'm still giving her money to make sure she reaches 125% of the Poverty Guidelines (and so she doesn't sue me for it, using the I-864). Do I really have to wait until she has worked ten years? When will this end?
As you seem to be aware, the Form I-864 Affidavit of Support that you signed obligates you, the sponsor, to support your immigrant wife -- and now ex-wife -- at an amount that's 125% or more of the U.S. Poverty Guidelines levels until she either:
-- earns 40 work quarters credited toward Social Security (approximately ten years of work)
-- becomes a U.S. citizen
-- dies, or
-- permanently leaves the United States.
The good news is that work that you did during the marriage can be counted toward these 40 quarters. So based on the facts that you've given, it sounds like she may have accrued four years worth of work quarters before your divorce, plus four from your work, for a total of eight years' worth of work quarters pre-divorce.
The bad news is that, as soon as your divorce become final, your work stopped counting in this manner. So, again based on the facts you have provided, it sounds like your former wife may have accrued one more year's worth of work quarters since the divorce, bringing her grand total to about nine years.
If all goes well, she will soon work another year, reaching 40 quarters creditable toward Social Security, and you will be released from your obligations under the Form I-864 Affidavit of Support.