I am angry at my partner, but the anger is not deep. I am more annoyed than really bothered. If I had to put a number on my anger from 1 to 10, I would give it a 3. Do you think I need to forgive, given that my anger is not intense?
There are different reasons to forgive. You could forgive for your own emotional well-being. You could forgive, on a higher moral level, for the good of the other and the good of the relationship. It does not appear that you need to forgive for your own emotional well-being, given how low your anger is. Therefore, you still can forgive so that the other feels better, so that you communicate better together, and so that your relationship becomes stronger.