Not Being Able to Get Over My FWB Relationship
So there's this guy whom I used to "cheat" on and we broke up 2 years ago. But recently we both had our fair share of relationship problems so we got this stupid idea of having a FWB relationship with each other. It obviously set fire to the rain and he broke it off. The thing is, I actually felt strong affections for him during our FWB relationship and I felt really sad seeing him move on with another girl. However he reminded me that it was me who "cheated" on him in the past so now I feel really terrible and I don't know what to do.
It sounds like a very difficult situation and I'm sorry you miss him. From what you wrote, you and your former FWB partner/ex-boyfriend didn't have a very good beginning. Even though you still have strong affections for each other, it still sadly wasn't enough to keep things afloat. It's okay to make mistakes, that's how we learn and it's okay to start over. It sounds as if it is better that you do then try to repair something that is already broken. I know it's difficult and I know it's hard but you're going to save yourself and him, so much pain and energy by looking forward. Sometimes when you really love someone, you need to let them go. Learn from the past but live in the future.
If you haven't taken a look at our self-help guide, we have one on breakups. I would encourage you to look through it.
I hope this helped, good luck and take care! 
Sometimes the hardest part isn't letting go but rather learning to start over. - Nicole Sobon
@limeWater9496 How old are you may I ask? When I was in my early 20's, I had my fair share of friends w/benefits (back then we called them skeeters), and it can be hard to not become attached to one or two in an emotional way, regardless you already know it's just sex. It can in fact damage you emotionally b/c you know the guy only likes you for how you look, not you as a person whole - at least it hurt me a lot and lead to stupider mistakes down the line. I would say, just move on and find someone that loves YOU. All of YOU. Not just what's between your legs.
@limeWater9496
It appears that you both gave it two chances - in two different forms of a relationship. Now there is a bit of emotion for him because of the thrill of the latest edition of your connection with him. However, now he's chosen to move on - probably seeking out what he needed all along. While it's good that you've been able to identify the things that didn't go right between you, perhaps that will carry over with you into your next relationship, where you don't make some of the same mistakes again.
It's good to feel that way about the situation and him ... but any attempt at interrupting what he has going now would likely be a mistake and not met with the warmness you might hope for.
However, it's your life - you decide what is right for you.
This is a scar you'll have to find treasure in once you're ready.