I'm having a problem with my best friend and ex.

So, I wasn't allowed to 日付 in middle school. Whatever. In seventh grade, I met this guy, Francis, and I really liked him and he liked me. We were basically going out. We held hands when the teachers weren't looking, he walked me ホーム every day, we sat によって each other all the time, even my step-dad gave him the "If あなた break her ハート, 心 I'll break your body" speach that dads are famous for.
About halfway through 8th grade I noticed he was spending a lot of time with my best friend Scarlett. She held his hand when we walked ホーム from school, sat によって him at lunch, and was at his house constantly. I shrugged it off, thinking it was nothing. After all, she was really clingy.
Then I find out that she liked him and he liked her. However, she was my best friend and I trusted her not toput any moves on my almost boyfriend.
Well, I shouldn't have because I found out that one of her フレンズ asked her (while he was still with me) if he was going to ask Scarlett out. Francis 発言しました he was seriously considering asking her out ASAP.
I asked him to choose and told her to lay off. He verbally chose me but the flirting didn't stop either way. So I broke it off with him.
Well now, most of my フレンズ say it's my fault. I should have just gone against my mother and gone out with him, または Francis would never do something that cruel and I must be lying. My お気に入り reason for why it was all my fault? We weren't really dating anyway.
Scarlett and Francis expect me to still be their friend, while they're holding hands and calling each other sweetie and babe, and after all they did to me.
I don't know what to do. Do あなた think I was out of line and should just suck it up? または do あなた think I deserve time away from them?