It depends on how you view it.
To forgive can be easy sometimes but to forget is where people get stuck.
In my opinion, to forget can be viewed from 2 perspectives:
You "forget" by not raising the issue/incident that led to your having to "forgive and forget" but have it somewhere in your memory.
You "forget" by actually forgetting in it's entirety the issue/incident without having it anywhere in your memory.
Objectively, no one can truly forget; especially where the incident or issue is so hurting or devastating.