As usual, I don't own Divergent.

Where is Tobias? I ask myself. If he was working late in the control room he would have told me. It's lunch time, so I go to the dining hall and grab a piece of pizza, eating it on the way to his room. If he isn't there already, I'll just wait for him. He's there already. But he's not alone.
I walk up to his room and hear moaning and giggling. Tobias almost never locks his door, and now is one of those times. Slowly, I open the door and have to cover my mouth to stifle a sob. Sitting on the bed, Tobias is in only his black boxers, making out with a girl, who is straddling him with only undergarments on. This girl looks perfect. Much more perfect than I could ever be. She has strait, dark red hair, and a tall, slender frame.
I slam the door and run. It doesn't matter that his legs are longer, because no one could catch up to me now.
I run, tears streaming freely down my face. Maybe he never loved me.
I am still thinking thoughts like this when I turn a corner and run straight into Uriah. I collapse into his arms, sobbing.
"Tris! What's wrong?" He asks. He guides me to the wall, where I collapse into a sitting postition.
"Four- h-He," I realize I won't be able to talk like this so I stop, and give myself five seconds to calm down. "Four cheated on me."
"What! That bastard. Are you sure?" Uriah asked.
"Uriah, they were sitting on his bed, with only underwear on, kissing! How can I not be sure?"
Uriah puts his hands up in defence. "Okay, okay, just checking that it wasn't a misunderstanding. Wow, I never thought he would do that."
"Me neither," I say. Uriah puts his arm around me, and I bury myself in his chest for a while.
We hear clicking footsteps coming down the hallway. Then I see her. I'm completely sure that she's the girl Tobias cheated on me with. She had straight, copper coloured hair, and a black skirt and white blouse on.
I stand up, startling Uriah. "You." I say.
"Do I know you?" She asks.
"Were you just with Four?" I ask. I hear a sharp intake of breath behind me; Uriah knows this is going to be bad.
"Yes, but I don't know why that's any of your business, little girl," she says.
Little girl? She is so not getting away with that. I punch her quickly in the jaw, then again in the stomach, and in the nose, until she is on the ground. "For your information, I'm his girlfriend, and I'm no little girl." I kick her once in the ribs, and hear a crack. I get one more to her head, knocking her out before Uriah pulls me away.
"Tris, this isn't helpful."
"Well it felt really good," I say.
He smirks, but says, "We should take her to the infirmary."
The dauntless part of me, and the part that hates her, and hates Tobias, is telling me to leave her here. But the abnegation part is saying, help her. So I help Uriah carry her to the infirmary, and we leave her on an empty bed.

Suppertime. I'm in line for food, holding a tray in my hands. I pull up the hood on my sweater to try and hide the fact that I've been crying. I feel a tap on my shoulder, and his voice. "Excuse me, have you seen a candor girl-" I whirl around and he gasps when he sees it's me.
"With red hair and a bitchy attiude? Yeah, she's in the infirmary," I say, with a proud look on my face.
"Why is she in the infirmary?" he asks, slowly.
"Because I put her there," I say.
"Why Tris?" he asks.
"You think I don't know? You think you can just pretend you didn't cheat on me, and I can just pretend I didn't walk in on you guys, and it'll all be good. Right?" I snap at him.
He pales. "You saw?" he asked.
"YES! I saw! You were probably too busy kissing her to notice me open the door, or sob, or cry into Uriah's chest for ten minutes!" I start yelling. The whole dining hall has gone silent.
"Tris,-"
"NO! You know what? I'm done. Why don't you go see your other girlfriend in the infirmary?" I slam my tray down and turn to leave, but Tobias grabs my shoulders and turns me back around, and crushes his lips to mine. I almost lose myself in the kiss, but I remember, those lips were just kissing another girl. I pull away, and slap him across the face, so hard my knuckles sting. Then I turn and walk away. Tobias doesn't try to stop me this time.
Before I know it, I'm in my room, laying on my bed, staring at the ceiling. I wish I could regret slapping him, but I don't.

I try to find it in me to forgive him, but I dont think I'll ever be able to. He doesn't even look like he's been crying, when I've seen him in the dining hall. It's been a few days since he cheated on me. He barely even looks at me. I pull out the note I've written, and leave it on the small table next to Tobias's bed, along with the spare key to his room.
Dear Tobias,
By the time you read this, I will be gone. Jumped into the Chasm. Hope you're happy.
You have been pretty much the only thing that has kept me from killing myself. Then I find out, you're sleeping with some Candor girl, and you don't even care, that I was about to commit suicide. I thought you loved me. I certainly loved you.
What really bugs me about the whole situation, is that you don't even bother to talk to me, or even look at me.
Well, the next time you go and sleep with some candor, think of me, and how you drove me to suicide.
Tris
A single tear rolls down my cheek as I leave his apartment, and walk to the Chasm. This is going to break Uriah's heart.
On my walk to the Chasm, I see Tobias walking in the direction of his room. I'd better make this quick, I think. I duck into a hallway as he passes, and run to the chasm when he's gone. With shaking hands, I climb up onto the cold railing. I can't back down now. Even if I wanted to, I wouldn't be able to. Facing the chasm,I bend my knees, and jump.

I know what you're thinking. You can't kill Tris! She can't die! Well maybe she wont! This is not exactly a one-shot, and there will probably be about 3 more chapters. I'm just leaving you in suspense! Muahahahaha!