Are you French and your wife English-speaking? That’s what the OP article mentioned as “école horizontale”. The author lived in France for years but her family spoke English at home and thus her French proficiency never got great.

In my experience living abroad, the fact that so many people speak pretty good English is both a blessing and a curse. We could have a conversation in French but it’d be pretty boring. So my friends and I always speak in English but I don’t get better at French.