Suggest that you make sure you're "moving on" first and then just keep in touch if you can keep it light and casual. As things are for you right now you might just exacerbate your sorrow.

I sometimes think so much of this pain is self-inflicted. People force themselves to believe there can be no other person in their lives than this particular guy so they set out to prove it, they close themselves to the great richness of relationships that are all different.

Chapter 8 of Cozalino's "The Neuroscience of Human Relationships" is about "Addicted to Love" where he gives evidence to show that similar chemistry is at work akin to any addiction. He says "Love and addiction share a loss of reason, an absence of self-control and an obsessive longing that must be satisfied." Further along in the chapter he suggests that a similar therapy as that applied to drug addiction may be the answer. Only a suggestion and I don't know how practical or "true" it is but it may be a way of looking at it.

I don't think that going out and looking for a new bloke is the answer as still immersed in sorrowful reflection it could result on taking someone up on the rebound, acting like a medicine: used until you cure yourself then you no longer have need of the medicine - in this case potentially discarding the person who has supported your cure. On the other hand the person could be the start of something far more sound and longer lasting.

Anyway, it's really up to you to decide. Can you email "lightly" enough not to stir an emotional hornet's nest? If he doesn't reply will that increase your anxiety? If he does, are you unwittingly reopening wounds? What if he is happy? Would that help you move on or bring even more sorrow?