[header] How to make a guy regret losing you [title] Keep your distance. [step] He doesn't get to decide when and if you talk again. Of course you need to respect any boundaries or requests of his, but if he's left it open, you choose when you'll talk again and how, be it via phone, text, or email. 
This may be difficult initially, but with practice, keeping your distance will be easier. [substeps] Your control over the initial communications shows him that he no longer has unrestricted access to you.