Is it possible to be bestfreinds with your ex.. who was my lover?

We have been broken up for about to weeks or so now and he talks to me still the way he did whn we were dateing but says were only bestfriends. Is this possble/ thing is i still love him!!!! and he says he still loves me.. but he one day skiped school on a free dayand hung out with three girls alone at his house and there's. telling me guys would also be with him. then he puts over 89 pictures oh him and these girls on is myspace page. And i try calling saying im in the er room and he has a girl answer the phoe saying a whole bunch of bs. and i txt him and say F&^% off... and now he knows i forgive him but he wont date me bc of what i said!!! who is really the bad guy??