How to tell when a boy likes you...?

me and my friend both liked this boy who would switch off liking eachother. then he told me he liked me and i liked him, we never went out.. and then he hu with my friend. and now he has a gf who lives half way around the country.....and shes a big SLUT!! but he still flirts with me alott!!! and i dont know if it is just because he likes me or because he is a player.......so does he still have feelings? bc i do???????