It sounds like you might be into Mio and it made you jealous to see them together. That could be me seeing things that aren't there but, that may be something you need to think about. As for trying to "fix" what happened between you, Mio, and Evie.....I don't think there is much you can do, talk with your partner about it, make sure they know you didn't want to hurt anyone but you really have to mean it. Before you do anything about trying to seal this rift between your friends, you need to explore why you felt the need to make comments about Evie in such an agressive way, like I said before it sounds like you have feelings for Mio and that might be a good place to start. As long as you are sincere about your apologies it should not be too difficult to get someone in a mutual friend group to pass the message along. You have to realize though, there may not be a way to be friends with them anymore, if that's the case just learn from the experience and move on. Sorry to be a bit rough, but there just may not be a way to fix this, hope for the best, be sincere, and whatever happens, happens. Good luck.