An illogical affair

Question

I need your help. One night, my wife tells me that she would go out with her friends for a while and come back at 11. Me, sleepy and drowsy, said "Go ahead." Now it has been four days and she is yet to return.

Even before she left, she was acting weird. She would sleep a lot later and would be a lot more drowsy during the day.

However, yesterday, she sent me a message.

From: [email protected]
To: [email protected]

Hello John,
Even though I said I would be back soon, that might not happen. I simply do not
like you anymore. It's not your fault, however. It was me. I cannot simply deal with the
pain anymore.

Mostly, You have always treated me with respect but I feel that I have not done the same.
Easily, you have done much more for me than I have for you. Our relationship is dead.

I know you, John. You will come for me. You are undeniably stubborn. Alright then. Try. Try
Venice, London, New York, you won't find me. Try India, Afghanistan, China, Japan, Korea,
England, Los Angeles, any boulevard you won't find me. I've hidden my tracks well.

Boring, John. That was what our relationship was like to me. You were satisfied with what
ever you brought home. You were satisfied with what ever you got as payment. Satisfied with what ever achievements you got. You did not have ambition. You did not want to do anything that is not necessary.

Kyle is a much better person for me. He matches my personality a LOT better than you, John.
I like being next to him much better. First of all, Kyle is so energetic and fun to be around. He is definitely MUCH better than you, John. Don't try contacting me, John. I am sure that I
never ever want to speak to you ever again. Please don't come to me John. I hate you
a lot. I've said this a lot now, but I'm sorry for being so hard on you. You know that I have bi-
polar disorder. John, all together, I am extremely sorry for leaving. Please don't push charges.
Perhaps, one day, we will see each other again. That day, we will finally be happy to be next to
each other. But honestly, for the way that you have treated me, you deserve to die. To die a painful death.

---

Once you read this, you were shocked at how weird the letter was. At one point, she was ready to meet you, and at the other, she was telling you to die.

As you are ready to close the mail, you see a riddle.

I have endless possibilities.

I am also found in schools.

Nowadays I'm common.

But not so common long ago.

Students use me for work.

Gamers use them to play.

But what I am shall be hidden.

Until you find what I am.

There is also ciphered text at the bottom:

Vvq icfi Z nsri nai yqiet, nai wkfei jeetg W ythmmfpsp, ibx pruh oxnr M dgbfxigiu.

1. What happened to your wife?
2. Where did she go?

Answer 1

What happened to your wife.

She was kidnapped. Reading the first letter of each line in the question gives, "HElp ME IVE Been KidnapPed"

Where did she go?

She being held at 11 Venice Los Angeles.

The answer to the riddle is (Thanks to @BeastlyGerbil for help cracking the cipher)

Computer

I have endless possibilities. 
I am also found in schools.

There are lots of different types? (or like @BeastlyGerbil mentioned they have a lot of processing power), most schools have quite a few.

Nowadays I'm common.
But not so common long ago.

Very common since the early 2000's. Before then they were much less common.

Students use me for work.
Gamers use them to play.

Many students write reports and do research etc. on them. Gamers play video games on them.

But what I am shall be hidden.
Until you find what I am.

Doesn't seem to be part of the riddle, but an extra line to make it flow better?

Next, using that as a vigenere key to break the cipher gives:

'The time I left the house, the first place I mentioned, the last city I mentioned.' Which are 11, Venice, and Los Angeles respectively.

Answer 2

Your wife

Has been kidnapped as the first letters of each line say 'Help me I've been kidnapped' - (Credit to @Dragonrage for this.)

and is:

Here, 11 Venice, Los Angeles.

---

The answer to the riddle is

Computer

I have endless possibilities. 
I am also found in schools.

Huge processing power, common in schools

Nowadays I'm common.
But not so common long ago.

Pretty new invention

Students use me for work.
Gamers use them to play.

Yup

But what I am shall be hidden.
Until you find what I am.

A computer

Next, using that as a vigenere key to break the cipher gives:

'The time I left the house, the first place I mentioned, the last city I mentioned.'

Giving the answer (thanks to Drangonrage for helping on this final part):

Your wife is being held at 11 Venice Los Angeles

Good luck!