Infidelity is unforgivable especially if you are married and have vowed in the eyes of the law to be with someone. It is also destroy a marriage or relationship.
Can you forgive them and give them another chance . Because of the welfare of your children if you already have and you do not want to destroy your family. Or you want to separate because you're hurt..
Circumstances matters, depends on what he/she do. And how big or how far he/she go in the infidelity. There are things that we can forgive but we can't forget. It's good to give chances but that doesn't necessarily mean that you are in martyrdom. It is just you have a lot of patience and love in your heart and once you lose all the patience then it's the end.