Your guy started dating this girl almost immediately after your break up? This means that the girl he is seeing could not necessarily be a rebound but a girl your guy knew while still in a relationship with you.You need to evaluate the situation and ask yopurself if you really want him back coz you love him or is it because he rejected you and got another girl and that you just want what you cant have(him) at the moment. If you feel that you want him back for all the right reasons and that your relationship deserves another go, then i would suggest that you withdraw and avoid any form of contact first be it fb, calls, texts or via any social site. Since he is used to you chasing him and reacting to everything he does like you did when he poked you, he will begin to question why you have suddenly grown distant and all silent, he will then start missing you and questionin whether he really made the right decision when he left you for another girl. At the moment keep yourself busy, and do stuff that you like. The grass is not always greener on the other side and he will soon realise that the girl he is seeing cannot offer what he thought you were not offering or what he thought you were lacking. As for now, accept the breakup and act like you are okay with it.