Is ejaculation during intercourse mandatory for defining vaginismus cure?
Not at all.
A cure is there when the woman owns her vagina = able to have all penetrations symptoms-free and at vaginal tempo.
All penetrations refer to finger, tampons, vaginal applicator for insertion of medications, gynecologic exam (finger + speculum), and penis or penis-size dildo.
Regarding intercourse, a cure is reached when the woman is able to have the penis enter and thrust. The ejaculation component is insignificant to the cure.
However, most every couple aims at completing ‘the act’ (penetration + thrusting +ejaculation) as a symbol of being cured.