Why is he doing this to me?i'm so counfused!?

you see, i'm new in my department and got to know my male colleague a couple of month ago. First time i met him we were just exchanging simple greetings, not much of the convo.then he found my profile in Friendster and i ended up giving him my e-mail add.not so long after that he got in my messenger list and we've been chatting every night though we're not that 'chatting' in the office.(he's always go for outstation & seldom in the office). i found out that he just broke off with his fianc�e and he told all of his problems to me.then he asked for my number and been calling & smsing me everyday. Talking 'bout everything & everything, even asking me to go out, dropped some pick up lines, compliment me & lots more. We even went out twice. I started have a feeling on him. But 2 weeks ago he stopped calling & smsing me, left me wondering. i did sms to him asking what happen had to him. he just said that he's busy. when we met in the office, he acted normally without saying a word. i mean at least he should tell me why is he now stop calling me or even sms me 'coz he'd usually explain to me everything. now everyday i keep thinking 'bout it & i'm so confused. he shouldn't do this to me.i wish he never started this whole thing at the very first. now i'm the one who suffers rom all this...