Why is he behaving this way?

After a couple months of dating, my partner and I had our first kiss/ played around etc recetly. Except now I’ve noticed hes tottally calmed down since thats happend. Prior to us being that close we wouldtalk on a dail basis , if not on the phone or on msn etc. Now hes stopped calling him self , unless I call him..even that he misses my calls all the time ..which almos tnever happend before. And hes entirely stopped coming on msn. Wth is going on. And not even that . The 2 or 3 times hat we have had short convos after it all.. Hes in a perfectly good mood. But then why the sudden disappearing/not calling or picking up calls act? Its really making me feel like crap and making me regret that fact that we made out and stuf ..as immature as that may sound. But its a cultural thing .any one got anyexplanations :(