How can I get him to fall in love with me again?

I started talking to this guy David, we hung out alot, and we were always calling each other, but one day he just kinda started slackin of, he would talk for about 5 mins and the convo was over, then one day he didnt even call, the next morning i woke up to find a message on myspace sayin "hey i really dont know how to say this .... but i dont think that we should keep talking as in dating ... i dont want to say why but im sorry .... i hope we can still be friends but i just dont think that its gonna work " so I figured out that it was another girl that he has liked for 5 months, i have the same problem, but i started blowing that friend off for David, and we planned on going to Sadie's together and I already bout his valentine's card... we had so much fun together and I want it back, he would look me in the eyes and smile, and we would laugh NON STOP and everytime that we were together was a new adventure, HOW DO I GET THAT BACK???