Don't let it win

I hate having negative thoughts and feelings like this. It's different from usual, because it's not about myself.
It's about her.
Now first of all let me make this much clear - I don't know her, I don't intend on getting to know her, heck I don't even want to meet her. I don't like her. For no particular reason. Or maybe for the reason that she's in love with him.
It bugs me so much.
It's ridiculous.
It bugs me so much I feel like I should get rid of her.
Kill her.
Erase her from existence.

I don't want to kill anyone, but there's just this feeling, like anger boiling in my stomach and I just want to get rid of her so badly. So that she wont have the chance of coming between me and him, so that there wont be the slightest chance that when they move in together he develops feelings for her.

I feel terrible for thinking he would ever cheat on me, but I just can't help it.
I shouldn't be thinking this.

I had really hoped that when she heard we were together again she would run away, turn around and never ever come back. Naive, right?
Why should anyone do that.
I'm not intimidating, I bet.
She thinks she still has a chance.

And what if she does?

He wants so badly to move in with her.
They'll do it.

I said I'd visit him.

I wont.

Not while she's there.

I'm afraid I'll just kill her then and there. Lose my mind and stab her guts with the nearest kitchen knife. Watch her insides spill onto the floor, hear the screaming, feel the blood.

That's kinda a weird thought.

Murdering someone in a jealous frenzy.

I'm going crazy, I'm sure of it.