Some people aren't able to apologize, but this isn't a reason not to forgive them. Actually as Sara said - when we forgive, we release not only that person, but ourselves as well. It relieves our soul and influenses pretty good on our health condition.
Sarah, you're from Russia, so you should know what actually the Forgiveness Sunday is. This is the day when everyone forgives others and asks them to forgive him. On that day I always say - We should remember to behave that way constantly, at anytime, not only on one certain day within a whole year :)
To forgive - Yes
To forget - No