Yes I understand the hurt, particularly if there was previously a great trust in the relationship, but in my opinion the human specie is not a very trustworthy animal at all, never has been, and most likely never will be. Knowing this, can we ever expect it. We are all very adept at making mistakes, and the only folk who have not made mistakes of one kind or another, are those who have never done anything at all.
No, I am not saying that we should forgive every idiotic act others make, but perhaps its a good idea to learn from it without letting it develop into hate, and hope that others will do us a similar favour. Personally, I forgive far too easily, and I don't hold grudges, I don't sulk, and certainly don't have tantrums. I just cannot be bothered with something that may be long past, but I NEVER forget, and it would be very wise to remember that.
Go on, patch it up. its a long time ago, just admit it was a regrettable incident. Quite pointless to get you knickers in a knot about it. Pity of course but..........