Poor Helen ! How could it be accused of failing to keep Carol while the union was in any case doomed to failure from the outset !
Their marriage was, let us not forget, above all, a marriage of convenience and we can say that Helen was sacrificed in this story without being asked her opinion.
It was primarily for King Ferdiannd and Queen Marie of Romania to get their son into the fold. But Carol was an unstable apparently quickly tired of his conquests. Thus, he did nothing to keep Zizi Lambrino he had married without his parents are aware and that he even had a child. This was his first abandoned home. Why then would it not again later? What he did actually abandoning helen and Michel.
If he was may be charmed by Helen very early in their marriage, he tired quickly, preferring to attend women less conventional than Magda Lupescu who manages to retain him the dominant mainly through the senses. Helen was too convenient for him. Because, rebellious and unruly, he needed to find a woman in the pretext of defying taboos and upset the established order.
Maybe if Carol had not met Magda Lupescu, he remained married to Helen, while leading a double life, but save face before the world as it was then for many royal couples at the time. But they would not have been happy together.