An Ankoù
Landlord.
I haven't checked that out and I might be wrong, but I think you're mistaken. Being married to a French national carried rights and privileges that are not reciprocated by the UK. For example, I'm a British national living in France. Normally my right of movement between France and other European countries would be restricted in the same way that it is for British residents, but as my wife is French, we can travel where we like just as before because she has a right of free movement and I'm her husband travelling with her. Another example: on applying for a post-Brexit resident's card (carte de séjour), a Brit living in France for more than 5 years can apply for a 10-year card, but one living here less than 5 years can only apply for a one-year card, renewable until he or she has been here for five years. He or she also has to provide prove of income, health cover and loads of other stuff. Since I am married to a French national, all I have to provide is proof of residency- the period doesn't matter- and no proof of income, tax paid or anything else to get my 10-year card.Previously the family could chose to live where ever they liked but let's just say it was a Brit and a French national. Now, if they are living here in the UK and decide they want to move to France on Jan 1st, there is no automatic right for the Brit to live in France.
Conclusion: The French (I can't speak for other European countries) wouldn't dream of separating partners. If the French spouse came back to live in France then the non-French partner would be expected to come as well. If I'm wrong in this then I'll stand corrected.