Hi all,
just I try in the law we have now in germany:

One selects one of both names as later familiy name. This is what (later) childrens will be named. Older childrens may be renamed to it.

If the others name is used for familiy name one must declare on out of three names for the last name:

the familiy name or
the own name before wedding or
a combination of both familiy name-own name or vice versa. Except the name of both before wedding was identicaly.

It gots more tricky if one of both is already divorced and carrys the old partners name (or the old double name).
In that case this could not be the familiy name nor can old double name(s) be converted to a triplex or quadruple name.

What puzzles me best are those couples that keep there own name and wore no ring. ::)

But there are good sides on it. I know a couple with the name pair Jung / Alt (Young / Old). Despite some little problems answering a telephone call, I would you keep such a name. ::)

Agnes