Well, according to the programme, it became dangerous for an English person to be in France, or a French person to be in England at that time because of the paranoia and bloodshed created by the Terror. Wordsworth had to flee France for his life, but he was not allowed to bring Annette to England because her life would be in danger as the Empire was against the revolution.

Annette continued to write to Wordsworth, updating him on how their child was growing, and how she missed him. The letters never reached him-- they were seized by the French authorities and I think, but I can't be sure, that Wordsworth had to forget his wife and child and try to start anew. At least during the Terror.