Legal Question in Family Law in Louisiana

No. Community property is not affected by fault. Having sexual relations with another person before divorce (even if the petition for divorce has been filed, but just not "finalized") is adultery and is grounds for immediate divorce. Someone who is at fault in the breakup of the marriage (and that certainly is fault) can never get spousal support, but their right to 50% of the community property is unaffected by the adultery. Moreover, if you settled the community property, the adultery would not vitiate your consent to the settlement. In short, you can now get an immediate divorce and keep your ex from ever getting alimony, but you can't undo the community property settlement.