Why are breakups so hard?

I was in a toxic relationship for the last 2 years but it felt like a decade! The problem was not wanting to end it, we both wanted to keep trying. I felt so drained. 2 weeks now since no contact, I lost the urge to even call him. There's no point talking to a brick wall. I blame myself for even staying that long. I love the feeling of relieve. I guess I will stay single for a while. I can't risk another heart ache! I value my health and peace of mind it took long to come here , wheeeeew