Well it has to be said that actually he may take your number with no intention of calling. Perhaps he already has someone in his life and was just being nice. Sometimes it can take him up to a few weeks to call you. Well he doesn’t want to look desperate so he plays it cool. Whatever the reason, it’s not worth spending your time wondering why you haven’t heard from him. The fact that he’s not calling is the only message you need. Time to let go and move on!
That’s one reason why it is never a good idea to force your number on him or ask him for his. If he’s not going out of his way to get your number, then giving it to him is probably going to lead to disappointment and will be a waste of time. If he thinks you are too pushy then he’s definitely not going to call.
If this is something that happens to you regularly, then you may want to evaluate how you come across to men when you first meet them. One thing that lets some women down is that their enthusiasm, when they meet someone whom they are hugely attracted to, can be very intense to the point that it comes across as desperation. This could be the case if you latch on to the first man who shows you any attention and won’t let go.
If he’s a bit shy, then he may not call if he wasn’t sure whether you were interested enough. Work on flirting with men so that you can indicate interest without coming across as desperate.
However, if he is available and he knew you were interested in him, then either he wasn’t attracted enough to you or you did or said something to put him off.