Is OTHER wrong in the post ? POST : So this Is a little complicated, but it’s been playing on my mind so I thought I’d ask the expanse of the internet.
A friend of mine Allie* (21F) has been my (21F) best friend since we were 14 at high school. 
She’s always been a little competetive with me for whatever reason, and thankfully competing with me for a guy hasn’t cropped up. Til now. 
Many many months ago I left my abusive ex, and my glorious rebound was a friend from Uni, who had been my lab partner. 
He wanted to date, I didn’t, but fwb was sweet. All good on both sides. He then met Allie*. 
He then tried (and failed) to have a threesome with the two of us, and then proceeded to move on from this idea to just wanted fwb with me. I still felt a little weird but sure. 
Both of them told me off their own backs that neither of them wanted just each other (I.e wouldn’t screw each other behind my back).
Well oops what do you know, little me finds out they screwed. Less than 6 hours before he and I did later that night.
Neither bothered to tell me, and when I did find out, they both said ‘we just didn’t want to tell you’.
Okay.
Sure. Move on with life, not my boyfriend. But as I’m not happy with sharing, I move on and stop sleeping with him.
I was then told they had stopped sleeping with each other, and he wanted me. I naively said I would think about it.
So I did, decided I was free enough from the ex that I could tentatively date and told him so.
He was being super weird and I thought it was weird, but whatever.
Find out they had started dating, and once again neither decided to tell me (also weird as she tells me everything, always), but now he wanted to date the both of us.
Um. No thank you. I told him as such, and moved on with life. 
His main explanation was that she was cute, and that I wasn’t enough for him.

Start seeing current boyfriend, all is happy, yay.
Get a message from Rebound saying that he didn’t know why I was dating anyone when he knew I wanted him (nope) and that I loved him (whatever bud) and that seeing someone else was my futile attempt to distract myself.

I then went overseas, and Allie decided that she would be picking me up from the airport when I got back. Sure, okay.
While I’m away, boyfriend asked if he could meet me at the airport too. Yay, be good to see him, two of my favourite people both meeting me. 
She proceeded to have the largest tantrum I’ve seen in recent times, saying I broke her heart, no one else even misses me, how dare I hurt her, my boyfriend doesn’t deserve me, how could I do this.
Rebound then messages me saying I was a horrible person who breaks promises, and I was stabbing her in the back just like I had my ex (ya know, the abusive one. He knew the details about that.) and that I was a cuck, and if I had any human decency I would let her do as she pleases. Also told me I was a master manipulator and to pull my head in. 
So back I come, after organising another ride home from the airport (because fuck that), and she proceeds to tell me she ‘won’ the Rebound. 
He insults me around her (sources confirm) and she agrees. Calls me a bitch, she agrees. But whenever she needs something I’m the first person she runs to.

I just dont know what to do. WIBTA to just cut my losses? I’ve tried just seeing her but she ‘surprises’ me by bringing him. 
Sorry for the wall of text, I will happily clarify anything.
Tldr I have no idea what to do.
