I was divorced and my ex-wife re-married but that marriage was annulled; can she now seek alimony from me?

This may be the first such case.  it is my view that the remarriage on its own eliicited the change in spousal support in your divorce agreement, assuming that is the source?

This is a difficult question to answer without knowing the terms of your original divorce decree.   Am I assuming that there was no alimony awarded the first time around?  Was it awarded but terminated upon re-marriage?  Did you even have a written agreement on the issue?  Is your ex NOW seeking alimony?

Generally, alimony awards are based upon the need of one spouse for financial support, and the ability of the other spouse to pay.  Alimony is more likely to be an issue in a long-term marriage where the earning capacity of one spouse is significantly lower than the earning capacity of the other.  Alimony also comes up in a marriage of any length if one party is unable to work and may be forced onto public assistance in the absence of an alimony award. 

Alimony awards are less likely in a short-term marriage, or where both parties have relatively equal incomes and earning capacities.  If alimony is awarded in the context of a short-term or medium-term marriage, it is more likely to be time-limited.  If the payor spouse has a large and long-term child support payment to meet, an award of alimony to the payee spouse while child support is being paid is less likely.  

You need to seek legal help in your area and give the attorney all the facts as it pertains to your marriage and divorce.  There are too many variables here.  It would seem unreasonable to allow your ex to obtain money from you after the terms of your divorce have been finalized but you need to make sure.