Time, and just getting up and getting out. You need to go thru the stages. First be sad. Eat or drink whatever to make yourself feel better. Then you get mad. Think of new names to call th person, or imagine ways to get even. Then think about all the things you wanted to do and that person didn't. Then go do those things! You will soon realize you are enjoying life again and doing things you like. Then find someone who likes the same things.
It can never be healed unless the real reason is found. Could you question the initial reason of a broken heart? Our hearts should not hurt each other, but why we kept hurting each other? What's wrong?
The initial reason might scare everyone of us. Something in our society could have been wrong for thousands of years.