They celebrate their ten year anniversary? The correct solution now suggests that they will celebrate for 10 years. Fun, but I don't think that is what it means :)
Well, actually that can be the meaning in Romanian as well if you don't add what they celebrate. "Ei aniversează 10 ani de căsnicie" would be less ambiguous, translating to "they celebrate ten years of marriage".
Thats how i understood it lol