What legal options are available to a spouse to prevent a divorce from being granted?

United States

I am an attorney who practices in family court. Most states are "no fault" divorce states in which you can merely assert that the marriage is "irretrievably broken" as a basis for a dissolution of marriage. Now, if the other partner answers the petition in writing to the court denying that the marriage is "irretrievably broken" the court may require the parties to undergo some marriage counseling to determine if the marriage can be reconciled before granting the divorce. However, judges will not force parties to stay married if the petitioning spouse still wants to dissolve the marriage.

UK

If you apply for divorce and your spouse refutes it, most Judges accept your application irregardless of your spouse's response on the logic that if one person wants a divorce then the marriage is over.