We can not confirm nor totally deny this matter during the Ghaibah of the Imam (AS) as it is part of the personal life of Imam Al- Mahdi (AS) which is kept by Allah as secret and away from the public knowledge.
Some narrations mentioned his marriage and children but our leading scholars did not find such narrations authentic enough to establish a confirmed fact. Many leading scholars openly refused such narrations like Shaikh Al-Mufeed and Shaikh Al-Toosi and Shaikh Al-Bayadhi.
We have narrations refuting the claim of his marriage, such narrations are mentioned in many books like Ethbaat al-Wasiyyah by al-Mas'oodi, page 201, and Al-Ghaibah by Shaikh Al-Toosi, page 134, and Dala'il al-Imamah by Al-Tabari, page 130, and Al-Irshad by Shaikh Al-Mufeed, page 366 (Arabic edition).
We may advise Mo'mineen to leave this personal matter of the life of the Imam Al-Mahdi (AS) to the Imam (AS) himself when he will come back to the public life.