According to the provisions at Point a, Clause 2, Article 67 of the Law on Social Insurance, relatives of persons defined in Clause 1 of this Article  who are entitled to a monthly survivorship allowance include:

a/ Children aged under 18 years; children aged full 18 years or older who suffer a working capacity decrease of 81% or more; or children whose father died while they are in the womb.

 Decrees and circulars guiding conditions for monthly survivorship allowances do not stipulate that children aged 18 or over who have a working capacity decrease of 81% or more but have a spouse are not entitled to monthly survivorship allowance. Therefore, you are entitled to a monthly survivorship allowance. You should contact the Social Security office of the district where your family resides to find out more information.