I've had this on/off thing with this girl called Sarah. We met around a year ago, we "dated" for around a month, then it was just a shitshow. She could never "get over her ex". She flaked on me and generally i felt like she just used me. That summer last year we stopped talking so much, and she went and fucked her ex (we were never officially a couple so she didn't cheat or anything). Her best-friend, Michelle, and I, always got along well when me and Sarah "dated", and i met her several times after me and Sarah didn't talk anymore. She often expressed how she felt like "Sarah treated me badly" and that "i was such a good guy, i deserved better". One night a few weeks ago, i met Sarah and Michelle at the bar. We talked normally, and Sarah went home after a while. Michelle told me she was into one of my friends, Michael, and talked to me about setting her up with him. I obviously wanted to setup some sex for my friend, so i did, and they went home together. Curiously enough, Sarah snapchats me for the first time in months after this, on a saturday, saying she was going out etc. That night i talked to another girl, and Sarah approached me and seemed to be very flirty with me, which confused me a lot as to why she suddenly seemed interested in me again.

So, fast forward a week, tonight, i was playing poker with Michael and some other dudes, and later we went out drinking. Sarah snapchatted me several times asking "where are you" and snaps of what she was doing. We went out, and i met Sarah, but she didn't seem enthusiastic about seeing and talking to me like i thought. Michelle is also there, but for some reason she is flirting with another dude, and not Michael. She goes home with this other dude. After a while, i suddenly notice Michael and Sarah outside the bathrooms in what looks like an embrace and it looks like they are kissing/making out. Not sure. Not gonna lie, i was kinda annoyed at this. I had told Michael all about me and Sarah's history and stuff. If he had talked to me about being into Sarah it would be different, but i felt like this was kind of a dick move from him after i set him up with Michelle. I confronted Sarah later when she approached me, saying "how would Michelle react to that?" and she just laughed saying "we were just talking" and denied everything. Sarah and Michael said they were going to get food. I was already on my way. At the shop, Sarah was sitting in Michael's lap and it seemed like they flirted and stuff, and i just felt really humliated. The queue was so long, so i just went over to Michael and Sarah, handed them my food-stamp, and told them to enjoy their night, then i just left.

Michael had obviously noticed i was mad, so he called me 30 mins later, saying he didn't fuck Sarah, and wanted to make sure we were still cool and stuff. He said he never wanted any girl to come between our friendship. I really appreciated him calling and we talked for a while about random stuff. He did admit he "would want to fuck Sarah if the opportunity came", claiming they both said "no" to sleeping together tonight and stuff. I personally think Sarah and Michelle are girls with really bad influence on us, and they are riding the CC pretty hard. Part of me kinda want to delete Sarah and Michelle from my snapchat and just forget about them, but i also feel like that might come across as a very "butthurt" move from me. Michael told me Sarah had noticed i was mad, and said she didn't understand why. How should i handle this? Pretty sure Michael won't delete Michelle and maybe she'll become a plate for him, and we are sure to meet again. How do i remain/regain frame after this, is it even possible?