Getting over an incident of cheating...

I decided to stick with my boyfriend after he hit up a girl and sent a dick pic too. She never even responded to him but the point is- although I decided to make this work, and I've come a long way in forgiving him, I still have a little ways to go. He understands this but it also makes him upset. It's okay to take my time right? I have every right to forgive as I can...