It can be hard at times, but for some girls it is no problem to be 프렌즈 with an ex.
The key is in how the relationship has ended. It's important that there is no anger and no one has cheated. If this is true for 당신 then it is 더 많이 than possible that with a little time 당신 two can go back to being friends.
프렌즈 and just friends. 당신 must be clear about what 당신 want. Sometimes when we pretend to want to be 프렌즈 with our ex, we are really looking to get back together. Sometimes this is what 당신 want and it works, but if it goes wrong then things will be even worse.
Give him space. If after some time apart 당신 still want to continue to spend time together without wanting to be a couple, then 당신 are ready to be 프렌즈 again!
-source: justjared T.V show<>