Why did he lie to me?

Okk so i was with this guy for like 1 month i know it was a short amount of time but i seriously did love him and i was head over heels for him but then on new years eve he broke up with me over facebook inbox and he basiclly hook up with my so called best friend and he told her that he never really loved me and that the whole thing was a joke to him and of course i was in tears now i know im 14 and i dont know what love is but even though he led and hurt me i still have feelings for him and i cant seem to let go i threw away anything that had to do with him i blocked him from facebook and well earsed him from my life except this was 2 months agao and i still want him and if this isnt love then i dont know what it is but all i want to know is why he lied and hookd up with my so called friend and why he doesnt even care?! some one please help me gett over this (it was a long distance relationship) and we talked on the phone for hours and inboxed eachter always and well you get the point he is my first love :(