Where did you hear about this secret love ? I heard that Helen did have one and was listed in her own diary, but the identity of the man is not revealed. I do hope it was the brother Apuila, otherwise it would sound too incestuous as he did marry Irene, Helen's sister...
Comments from some journalists do not clearly identify the suitor of Helen. One of the few to speak, the Romanian journalist Seicaru, wrote : " In 1928, Princess Helen of Greece had divorced Prince Carol. It was herself expressed and demanded the legal termination of marriage. Apparently this action, which had not been imposed, seemed to be the normal reaction of an outraged wife by driving her husband. But, in reality, the true cause was different and purely sentimental ... Helen longed to marry the Duke of Aosta she had known in 1925. But the marriage was made impossible by the opposition of the Church of Rome that forbade any marriage of a Catholic with a divorced woman. After Carol returned to Romania, Helen of Greece refused any reconciliation with her ex-husband because she still hoped to receive, from the Vatican for permission to marry the Duke of Aosta ".
However, it appears that the reporter was mistaken in asserting that Princess Helen wanted to become the wife of the brilliant and chivalrous Duke of Aosta, which at that time was already married to his cousin Anne de France !
At least, that both his brother Aimone who, having understood that he could never be the husband of Helen, has decided to stay still in the family by marrying a few years later, her sister Irene.