Most Helpful Guy
You can get over it but it's down to you to find a way to make peace with it. You can either spend a lifetime beating yourself up and/or hating the person that cheated or you can accept that you can only control so many things and you can let your hatred go.
I'm not saying that you should forgive and forget, just forget. Playing it over and over again just punishes yourself. The person you thought you knew was someone else. Accept that and let their memory go.
As for yourself, you can't control other people, you can only do your best to be the best version of you. If someone chooses to cheat then they will cheat. It's not your fault, they made a decision. There is no need to deconstruct yourself and it won't help anyway. We trust people because trust is required in a relationship. Trust is a leap of faith. Sometimes that trust won't be repaid. It's just one of them shitty parts of life. That's why trusting is brave and that's why being able to trust makes you strong.
You will get past this if you don't waste your time trying to replay the past over and over. Let go of it and get back to being yourself.
Most Helpful Girl
I think it depends on how invested in the relationship you are. If it was a long term relationship where being cheated on completely blind-sided you, then no, I don't think that would be something you'd get over easily.
But if you just started dating this person and you find out they're still screwing their ex (or something of the sort), it's much easier to dump them and forget them and their transgression.