Can you ever be again with someone you dated? Even if hearts were broken? How do these things work? What are the rules?
N., Murray Hill

Building hips with those that we’ve dated is always precarious.

It’s only possible if you have A Talk upfront, where you make it very clear that, although you value his hip, there's no chance of there being a relationship again. Make sure in the beginning that you're both on the same page. Set boundaries if you feel you need to, especially pertaining to things like personal space. Clear communication is the only way to make it work.

After that, try it out and see. It will likely take time to get all of the kinks out of the new hip, and adjust to being instead of lovers. You may want to limit the frequency with which you see each other at first.

Unfortunately, not everyone can make this kind of hip work, so if it really doesn’t work (he’s still interested in pursuing a relationship, for instance, but you really aren’t and feel uncomfortable with his intentions) you may just have to let him go.