Can I Just Be Done?

So just to forewarn everyone, this is another venting blog. I feel like I feel better when I vent.
So anyways. My friend, Emily, is one of my closest friends ever. She means so much to me and we have had quite the past. Especially since mid-summer to right now, mid-school year. Me and her had this little fling thing going, which I wanted to turn into something more, but it never happened. She ended up dating my ex-boyfriend/best guy friend and that just caused a whole ton of shit to go down. She ended up cheating on him with me to say the least. I won't go into detail. They broke up and I'm thinking We are finally going to be together. I thought wrong. She started dating this clingy bitch, Summer, and fell totally in love with her. Summer cheated one her. Not once, twice! Emily still went back to her.
For Emily's birthday she had a little party. I was pretty much alone with my friend, Jess, while all the other guests kept to themselves really. I'm not going to lie. I flirted with Emily right in front of Summer, but Emily flirted back. Actually she was flirting with me more than I was with her.
The next day I get a text from Emily saying that we couldn't be friends anymore. I literally ended up curling up in a ball in the corner of my basement and bawled for hours upon hours. I couldn't believe she was saying this. Fucking Summer didn't trust me around Emily so Emily had to chose her or me. She chose Summer. We spent the next week fighting non-stop.
Emily came over to my house and got back the stuff she gave me and I once again broke down, right there in front of her.
Last week Emily broke up with Summer because she couldn't trust her. (called it) So I texted her and asked her if we could be friends again. She said yes and that she missed. me.
Today, I find out they are now back together... What the fuck am I suppose to do?! I know for a fact that Summer is gonna make her choose again and I'm going to end up heartbroken like last time. Funny thing is, Emily always said that she would never chose a relationship over a friendship..
Just remember, friends are always there for you. Relationships aren't..
Thanks for listening to me vent guys..,
Taylor Elizabeth♥