Imam al-Shafi'i (may Allah have mercy on him) said: "Since Allah Almighty mentioned li'an for husbands without qualification, li'an applies to every husband whose divorce is valid and upon whom the obligations are binding, and likewise to every wife upon whom the obligations are binding."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب اللعان / Q15293