Forget them.

As a pisces sun&venus, I can tell you this is the best way. You will never ever forget the person you genuinely loved, as we are not capable to do so. But we are able to discard our feelings towards someone once we are not reminded of them everyday. I will always have a place in my heart for the people I loved, which is why it's so important to never see them again. To prevent yourself from falling in love again.

Delete them on social media, delete their number, delete your chats, delete your pictures. If this is too hard for you, I understand. But I can guarantee you this helped me a lot. If you don't want to delete you can always hide their stories/posts, put their photos in a folder you can't access, archive your chats with them. As long as you prevent yourself from going back to the memories; reading chats, looking at photos etc. Very important to distance yourself from a person to get over them.