You can forgive if you choose, good luck forgetting it. You certainly do not have to put up with any of it or keep either one of these people in your life if you don't want to. It might be difficult to trust again but that is really a personal thing.
Here's some advice a friend gave me you can forget what someone said, you can forget what they did but you'll never forget how they made you feel. It's up to you what you want to do. Good luck I know how you feel.
ok well u should i answered this i looked t someone the comments tp see if u said wht he did and if he kissed ur bff in front of u and we 2 were dating id say ask him why he would do tht so or not making mistake wit lossing him but at the same time u should forget meaning "forget HIM"