Does the husband's statement "May Allah curse me if I ever have relations with you again" uttered in a moment of anger, constitute an oath, and what is its expiation?

The man must seek Allah's forgiveness for what he said, based on the Prophet, peace and blessings be upon him, who said: "Indeed, a servant may utter a word pleasing to Allah, of which he thinks nothing, but for which Allah raises him by degrees. And indeed, a servant may utter a word displeasing to Allah, of which he thinks nothing, but for which he falls into Hell." Narrated by Al-Bukhari. No expiation is required of him other than repentance, and he is permitted to approach his wife. Ibn Qudamah said: "If he said: 'May Allah disgrace him,' or 'May his hand be cut off,' or 'May Allah curse him, if he does such-and-such,' and then he breaks his oath, no expiation is upon him." This is what the followed schools of thought hold. And it is not permissible for a wife to refuse her husband's bed except for a valid excuse.