פירוש על עבודה זרה 39:10

The objection comes from the action of R. Shimon b. Gamaliel who indeed praised God for creating such a beautiful gentile woman. R. Akiva does not really offer such praise for Turnus Rufus’s wife. The story is here because he does recognize her beauty. Turnus Rufus is the evil Roman emperor who decrees that R. Akiva should be tortured to death. I am not sure if the idea that he would marry his wife appears elsewhere.