You forgot to mention AoS
Don't follow.
Let's rewind here. Here are the facts:
1. It is not possible for an international married couple to stay together immediately and permanently in the United States. The foreign spouse needs a CR-1 or IR-1 visa to immigrate. Several months are required, a criminal history may be disqualifying, and there is a particular financial sponsorship requirement.
2. It is not possible for an international married couple to stay together immediately and permanently in the United Kingdom when one spouse is a U.K. citizen and U.K. resident, and the other is a foreigner (non-EU/EEA/Swiss citizen). Several months are required, a criminal history may be disqualifying, and there is a particular financial sponsorship requirement that's higher than the U.S. requirement.
3. It is possible for an international married couple to stay together immediately and permanently (or until U.S. or U.K. immigration permission is obtained) in any other EU or EEA country not the United Kingdom when one spouse is a U.K. citizen and can establish residence in that other country. The U.K. citizen is immediately employable in that other EU/EEA country though must follow any residence registration procedures (near identically to the procedures a citizen of that country follows). A U.S. spouse can enter without a visa and regularize his/her stay as the co-resident spouse of an EU/EEA citizen. As soon as he/she regularizes his/her stay (in country), he/she is legally employable. The U.K. citizen must demonstrate only an income (or wealth equivalent) above the social benefit minimum for that country, which is almost certainly the lowest amount among these three options. A criminal history is only disqualifying if local authorities can demonstrate that either person represents a serious and current security threat, a much higher standard than with either of the other options.
Note that Option #3 includes all EU and EEA countries, including even some of France's overseas territories that are geographically close to the United States. And of course Ireland and France that are geographically close to the United Kingdom. Visits to both countries are still allowed and still geographically convenient, as desired.
Of course Option #3 is a reasonable, excellent one for many couples. Of course it's worth mentioning.
Every couple is different, though as a generalization time apart can stress a marriage. The U.S. and U.K. have immigration policies that do not currently place much value on the stresses and strains caused by visa delays. The EU (and EEA) think differently, and it's certainly worth pointing that out.