The sole survivor will find his/her wife/husband has become horribly mutated like the master in FO1 and his son was killed by the mother/father for not wanting to assimilate with her/his army of highly intelligent centaurs. If the wedding ring is equipped while in conversation with her/him you will have a chance to talk her/him into self destruction as long as you have high enough charisma (90+) and luck (at least 5).