翻译 - 西班牙语-英语 - necesito verte, hace mil años que no te veo

Original form of the translation:
I need to see you, it's been a thousand years that I don't see you.

What do you think of "I haven't seen you in a blue moon"?

What about : I haven't seen you for ages !

Yeah, I like that better, actually, so I'll put the literal translation in the Remarks section instead!
Thanks, lilian!

Thanks for your version too, Angelus, but I don't think the expression "blue moon" (taken from the standard expression "once in a blue moon," meaning extremely rarely, i.e. an expression about frequency, not about the length of time as such) could be used in this way. Usually we can't take idioms apart and use just pieces of them (I try to do that in Chinese too, and often look foolish! ): they are usually kinds of all-or-nothing expressions that are not "dissectable"!