A spouse who has committed adultery may be entitled to less alimony.
If the divorce is in a state with a fault standard, the court may reduce a support awarded when one spouse can prove that the other spouse committed adultery, and that this infidelity is the cause of the irreconcilable collapse of the marriage. However, proving adultery places a heavy burden on the victim spouse. Most lawyers do not advise doing it, and in no-fault jurisdictions it may not even be possible.
Neither spouse has an absolute right to alimony. When the court awards it, the amount is specific of the case, and the laws about alimony vary from state to state. The duration of the marriage, the age and health of the parties, the finances and financial prospects of each spouse – all are factors that the court generally considers in awarding alimony.
The court may consider fault in the marital breakdown, but courts in most jurisdictions usually concern themselves more with economic misconduct, such as dissipation of the marital estate, than misconduct such as infidelity.