Why is "visitar a contigo"wrong? Why is it "visitarte"?
I'm wondering what the rule is behind this.
3 Answers
Hi!
It's wrong because "a" is a preposition and it isn't necessary. In english, you say "Visit you = visitarte"
"With you" is like "contigo" in spanish, so you needn't put the "a", but, "visit with you" means in spanish that you visit a third person with this second, for example, "you (shonacd) and me (we) visit Michael" ((tú y yo)nosotros visitamos a Michael).
In spanish, if you want to say visit someone and you've said it him, the correct form is: "voy a visitarte" (i will visit you / i visit you). You must indicate the person who is visited by you.
Sorry for my english, and i hope you understand something i've tried to explain you XD
PD: your english for my english in skype, native spanish 
Why should any language be the way you fancy? You expect it to be "to visit to with you", since 'contigo' means 'with you', which sounds weird, to say the least. We say it almost like in English (visit + you), but the words are written as one: visitar + te. I don't see the mystery here: why is it so similar to English instead of looking weird?
Well, for one you are trying to make an odd combination of two different prepositions (i.e. "a" + "con").
In any case, the verb visitar is transitive which means that it is unnecessary to introduce the direct object with the preposition "con."
If you want to visit a person (i.e. go see a person) then you could either use the direct object pronoun as has been suggested to you (visitarte) or you could use the "personal a" to introduce the direct object (Quiero visitar a Marta).
If you were visiting a place (i.e. going to some country, etc) then the "personal a" would be unnecessary (Quiero visitar España). Here it would also be possible to use a direct object pronoun if the place in question has already been identified (Quiero visitarlo también)
