When I was looking through the official marriage papers you submit when oficially requesting marriage, to see what I need to do if we would want to get married, that option simply wasn’t there in the checkboxes. And I asked for clarification, and apparently our laws don’t allow that combination, at least not as a part of the marriage process.

I haven’t really looked into it more, and a friend told me it’s very probable that we could just choose one of the available options and then submit a separate request to change my surename to add the missing one. It was also more than a year ago, and someone also told me that our marriage laws did go through a revision recently and it might be actually possible to choose both for both now. I’ll have to re-check again, but I’m certain that at least last year, it wasn’t possible.

Oh, one option I found a funny loophole was that we could marry, she’d take both, then divorce while keeping our new surenames (so she still has both), then marry again and I’d take both. I would end up with three surenames, mine twice (since she already has both, and I’m keeping mine and taking her current at the point of second marriage), but while that would be pretty funny, realistically it’s easier to just file for a surename change after wedding :D

As for the reason, who knows? But an ancient patriarchic custom is probably the reason, I’d guess that especially historically it’s not really common for a man to take his wife surename in general, and usually it’s just the bride either taking the man’s or keeping both.