How do I act around him?

So ive know this guy for about 4/5 years and we lost our virginity together and kind of dated for a while behind his parents back (our parents are close) then on my birthday he decided to bring his "girlfriend" (it only lasted a week) and i had no idea who she was to my birthday party and last weekend he was all cosy with avdifferent girl (who i know but dont really like) now hes getting all touchy feelly with me (which he normally doesn't do) and i don't really know how to act around him. help