Men!!!!
I really hope you hear from him soon - maybe he's on holidays and hasn't checked his e-mail. Or maybe he has a new e-mail address.... There are millions of reasons he could be delayed in responding to you.
If you don't hear from him, do some research (I don't mean hire a PI or anything!!!) but you might find out he's with someone else (in which case he might have felt awkward in replying to you) but either you turn into a stalker and sit outside his house with a box of donuts and wait to see him on his own or alternatively close that chapter of your life, be open minded, forget making comparisons (and it is a lot easier said than done), and you might just find that one of the other guys is the bees knees and the cats pyjamas and end up madly in love and live happily ever after.........
I have my fingers crossed!!!!