Why does he still call?

we broke about a year ago but I'm still in love with him. he calls me almost every night, even though he has a girlfriend. he claims that I'm his "best friend" and he tells me everything but why doesn't he understand that when he talks about his girlfriend it's like a dagger to the heart. why does he still call me? why am I still in love with him? is it normal to still be in love with someone who dumped me almost a year ago? I've been having a really hard time with it =[