Are there some couples applying to do a LL.M. this year?

Yep.

Will you go only if your wife/husband is accepted in the same university too? Are you informing in your application about this special situation?

We didn't inform the university about our situation, and we don't share the same last name, but luckily for us, untill now we both got admitted (2 of 2) and one of them was our first priorty, therefor it doesn't matter anymore... we just hoped for the best and that's what happen :)

and we knew that we'll choose the university who admitt us both...

If your in a relationship, it might be a good idea to do your LLM in the same school, even though this may limit your social life. But that's still better than breaking up --- and that's exactly what happens in many relationships when only one partner joins the LLM crowd.