(((hugs))) There are many members here who have "similar" experiences that haunt them.

It takes a strong countering, and plenty of time, until such an event will stop impacting you so negatively, upsetting your current life. Whenever that horrible picture comes up in your memory, quickly replace it with a suitable one. It could be of a picture of him and you having a wonderful time (such as you might have a photo of) or of something religious or even scenic... but it needs to be of good memories, imo. So when your brain pops that tough pic up, you switch immediately to a pleasant memory instead...

You won't ever forget, but it will ease over time.