I'm telling you right now: I don't know the key secret to moving on. All I know is that there comes a point where you decide, do I care about myself enough to take care of me first? And that's when you make changes. That's when you cut out toxic people. That's when you end friendships/relationships who betray you. That's when even despite all your history, you decide to let go. Because your own mental and spiritual well being has to come first to be able to be happy.
And when you finally make these cuts, there's relief. Relief from standards and expectations you were holding yourself to to please someone else. Relief that you aren't going to have to put yourself in the situations that make you feel the worst about yourself.
Grieving comes with it all, grieving the connection you lost and the good memories you have. It will come with pain, and depending on the type of relationship, a lot of it. But you're taking steps to making a better life for yourself. A happier life, filled with more love.
So if reading this made you think of anyone, maybe it's time to reconsider. I hope you have the strength, support, and love to make the choices you need to make for you. How you feel matters, and you matter.