Have you noticed the crack getting longer? If it isn't and it is not hurting anything why bother to try to "fix" it?

If it is growing I see 2 choices. Crack it on purpose and decide if you want to glue it back together and have a wider hone or the way I would lean and make 2 narrower hones out of it.

If you tried the gluing together thing and that didn't work you could always cut it again along the repair and have 2 narrow hones.