Well you're understandably angry and jealous, whether or not anything actually happened is a different story.

From where I'm standing tho, (and if I'm reading this right) you're directing your anger at the wrong person.

You 2 were broken up when this girl tried to enter the picture.

So by that logic alone, she didn't overstep a boundary, your bf was single.

Also, how did she know he was up for grabs I wonder... I mean you say she's "slutty" but they've known eachother forever, so why if she's as skanky as your bf says, does she wait till he's single to make her move? And who told her he was single, I mean a month isn't long at all, so gossip about your break-up must have spread far and fast.

Anyway, your bf was a single man, so she doesn't deserve your rage.

Buuut,
How'd you find out about her?

He told you, knowing it would make you jealous. I mean why else would you tell the girl you JUST dumped about another girl persuing you?

Idle chit chat?

I think not.

Your bf dumped you, then played jealousy head games with you, and now you hate a girl who doesn't even know she did anything to you.

On the other hand;
If she tried to jump his bones knowing he has a gf, then yes, by all means rage at the girl, rip her eyes out if you must. Lol

Or not. I wouldn't (not anymore anyway ), because after the insecurities and jealousies subside, other girls seem sad because they want what I have.