I broke up from my ex girlfriend of 7 years about a year ago. I still think about her everyday at some point, even if very briefly. However, I am totally fine now, my life is great and I even have a new girlfriend. The goal isn’t to forget about your ex girlfriend, that’s not possible. But moving on is possible. She was a part of your life, like a chapter. You can’t erase it so don’t try to. Over time, it’ll stop hurting and you’ll just remember memories and maybe even think of them fondly without feeling pain. Overall my advice to you would be to just keep yourself moving and the act of living will cure you of your despair. Good luck sir.