One of my areas of focus as a therapist is trauma, so I've worked with many people who have wanted to forget certain memories. Unfortunately, it is not very easy to purposefully forget a memory. Especially not a memory that has strong emotions attached to it.
I recently tacked the concept of if it is possible to forget a memory for Choosing Therapy and discussed the options you have when it comes to memories you would rather not remember. Though it may not be possible to erase a memory completely, there are coping skills, techniques for weakening memory activation, and multiple empirically backed types of therapy you can turn to if you are struggling with difficult memories you wish you could forget.
If you are interested in learning more about how to forget, or at least weaken painful memories, you can head over Choosing Therapy. There, you can read my article about How to Forget Something on Purpose.