Most Helpful Guy
You can't. If you have ever been in love with somebody, you cannot see them as your friend. It's literally, and probably psychologically impossible. You cannot just stop being in love with someone overnight. Constant exposure to them makes it even harder, and it will slowly kill them inside. Usually, one of the two loves the other one "more", and that person tends to be the one to disappear after the break-up, while the other person wants to remain friends, because they were not in love anymore, so it's easy.
The only way you could actually stay friends without destroying yourself if you love them, but were never in love with them.
This is from experience. Let them go. Let time pass by and when they have moved on it may be possible to become friends again.
Most Helpful Girl
I'm actually really good friends with my ex and it's because we have mutual respect for each other. We initially started off as friends and because I liked him so much as a person it eventually progressed into a romantic relationship. But after a few months of dating, we decided that we only had friendship feelings for each other & we went back to being friends. It was really easy switching back to friendship because we have always been very respectful and had a strong foundation that we built on :) I think respect is huge when it comes to staying friends with an ex :)