Along came Kirstin

I don't know

*third person POV*
The next morning came around and both were already awake. Not much sleep happened and a lot of puking and random jumping around happened. Kirstie was acting very strange and Avi had a good idea of why she was like this.
"Kirstie, let's go to the doctor."
"Ok..."
They headed to the doctor and Kirstie sat nervously.
"Don't worry, I'll come back with you."
Just then the doctor called them back. Kirstie grabbed Avi's hand and walked into the room.
"Hi, Ms. Kirstin. I'm doctor Smith."
"Hu... Hi.."
"So can you tell me what you're feeling right now?"
"I um... I feel kinda sick, but sometimes I feel happy."
"I see... Is there anything strange that you might have eaten or done to make you sick?"
Kirstie hesitated to answer Avi took over.
"Doctor, Kirstin and I had sex, and it was her first time..."
"Oh, well, that shouldn't cause any problems."
"She also says she gets regular periods and her last one ended last week.... And just recently I've taken her into my home."
"I have a few tests I can run on her. Kirstin follow me."
Avi waited patiently in a separate room for them to get back.
"Well Avi, she isn't pregnant."
*Avis thoughts*
What? That's the only explanation. How can she not be pregnant?
*third person POV*
"In fact we found that she can't have children at all. The reason she is having the sickness is because her body is being introduced to so many things that are new to her too fast. The natural response is the reject what's happening. Don't worry, it will go away. If you continue to expose her body to new things so quickly it may take some time for the sickness to go away. Just be careful."
"... Um, thanks doctor."
"Anytime."
Kirstin and Avi left the hospital and went back home.
"Avi... Why can't I have children?"
"I don't know..."
"I'm sorry I can't..."
"No no... Don't be upset, it's not your fault."
"You're not mad?"
"No of course not. I will love you the same no matter what."
"I still feel sick."
"I'll take care of you baby, we're almost home."
They pulled up into the drive soon after and walked inside. Kirstie ran to the bathroom to throw up and Avi waited.
"I'm sorry you have to feel this way love."
"It's ok... The doctor said I'll get  over it."
"I love you."
Kirstie didn't answer and walked to sit on the couch.
"I'll make us some food."
While Avi was busy, Kirstie went to her room and gathered some of her stuff. She once again planned to get away. She packed a small bag and grabbed some of Avi's money and made her way out. Avi still oblivious to her leaving. A few minutes later Avi finished what he was doing in the kitchen and walked into the living room to find Kirstie. But obviously she wasn't there. He called her name several times throughout the house and never got a response. When he got to his room he found a note on his door.
*kirsties note*
Avi, I know you've said you love me. But I don't know if I feel the same. I just don't think I'm doing you any good. I'm just a distraction and keeping you from moving on in your life. Thank you for showing me things I didn't know and showing me what sex is. I enjoyed it a lot. Maybe we'll see each other again. Please don't come looking for me. I'll be fine. Also sorry I took some money. I hope you don't mind. -Kirstie
*Avis POV*
I can't believe she just left like this again. Why doesn't she understand I love her. I'm not listening to her note. I will find her. I need to call Scott.
*third person POV*
"Hey Scott, I need your help."
"What is it?"
"Well... I've recently taken in this girl who isn't exactly with it, she doesn't have much and doesn't know what a lot of things mean. I've fallen in love with her in the process of trying to teach her what things are. But she doesn't believe me that I love her and want her to stay with me. She ran away and told me not to come looking for her. But can you help me find her?"
"Wow, I uh... Of course, but I have no idea where this girl would be."
"That's ok, I just need you to come with me."
"Yeah, I can."
"Ok, I'll pick you up soon."
Avi picked up Scott 20 minutes later and drove to Kirstie's old house. He ran inside and Scott followed behind.
"Wow, this is her house? It's kind of... Terrible."
"Yeah I know, her mom left her when she was 11 and didn't have much money."
"What about her dad."
"She's never met him."
"That's sad."
"Well she's not here. Let's go."
After 2 hours of looking around town, Avi didn't find Kirstie. He got frustrated and gave up for the day. Later that night Avi sat on his couch and stared blankly into space.
*Avis thoughts*
I miss her.. Her smile, her hair, her laugh, her voice... I don't get it, if she didn't even know what love really was, then why is she so resistant to it? I've had sex with her!? Did she actually enjoy that? Maybe she been lying to me about all of this from the beginning.
*Kirties POV*
I'm cold, so cold. But I can't go back to Avi. He'll just say he loves me again. He lied to me about love. He's just going to hurt me... Like mom. This alley is gonna have to do for now.
*Scotts POV*
Man I feel bad for Avi. He seemed really determined to find this girl. God, when did it get so cold out here? I sure hope Avi finds this girl again.
*third person*
Scott was walking down a street in the city a few days after him and Avi looked for Kirstie. As he passed the local library he heard an echoing cough. He stopped when it sounded rough. When he looked down the alley he passed, he found the source of the coughing. Slowly, Scott approached the girl.
"Miss... Are you... Ok?"
"Yeah... Yeah I'm fine."
"I heard your coughing, you don't sound very good."
"Please, just leave me alone."
"How about I buy you some coffee."
"I don't know... The last time I was in a coffee shop I got into something I shouldn't have."
"I promise nothing bad will happen."
"Fine."
Kirstie stood up and followed Scott to the coffee shop.