"Apology accepted. Trust Denied."- Unknown
Betrayal is one of the hardest things you can experience, and you may feel it's your fault. But I promise you it's not. It's not your fault that someone decided to back-stab you and treat you poorly. It's that persons fault for not valuing you or respecting you.
In my own life there was someone who betrayed me and treated me badly, and they didn't even realize they were doing it. They still see me and act like we are normal and so close. It's very hard for me to not go off on that person give them a piece of my mind. However, I realized I don't want to stoop to their level.
The hardest part is the person doesn't realize what they have done.
When confronted, they act aloof and like they're never wrong. They act like the situation they created did not even exist. If this was a year or two back, I probably would have gone off on that person and made them feel how I felt, but I have grown and matured and realized that I don't need to yell at someone or cuss at them to prove my point. As great as it feels to be the bigger person, it still hurts that someone you cared about and trusted does you wrong.
How to get over it? Realize that its not your fault. You didn't make them behave like that - they did it themselves. And by betraying and hurting you, they ruined your connection. It's okay to not want to stay friends with them or hang out with them you need your space. Another thing is it's okay to feel like you want tell them off, but don't do it. It may seem like a good idea, but it'll just make a bad situation worse. Just let it go and move on.
How to handle being around that person? Well, it may so happen to be that this person is in your friend-circle, and you still have to be decent and civil with them. You can't hate them no matter how much you feel like you do. Hating that person isn't going to make your situation better. You will still feel bad either way. Just be as kind as possible. I'm not saying to be all over them, but be nice and civil.
What has betrayal taught me? It has taught me to not be so open and so giving to people who don't deserve it. Betrayal taught me to be a little more guarded. I'm still friendly, but now I have boundaries. Betrayal also taught me that I don't need to like everyone, and not everyone needs to like me. I've been in a situation were someone who was very close to me did something they didn't realize was wrong, and no matter how much I tried to explain it to them, they remained aloof and pretended like nothing was wrong. But I realized that I can't change people. Feeling sorry and remorse comes from within. In life, you will deal with people who, no matter what, will not admit to being wrong they will be never be able to understand your feelings. Unfortunately, you will deal with people who just don't care about your feelings and have no regard for your emotions.
I have also learned to appreciate the people in my life who are real, genuine, and have proven to have my best interests at heart. I am thankful for all of the loyal people in my life, and I have learned to not care about the "fake " people who were just part of my life, temporarily. Just be positive happy and focus on yourself.