If a guy is flirtitious with his friend then gets a gf?

He was always flirting a lot with his friend who is a girl (lets call her Sara) until he got a gf, lets call her Jane. And I mean flirting with real heavy hints. When he was flirting with Sara, even then at the same time he was spending time with Jane- the girl who is now his gf. Sara didnt know this then. Jane officially becomes his gf, he tells his Sara (ofcourse everythings gets very awkward when he is about to utter something flirtitious and generally awkward) What does this say about him? The friend hasn't developed real feelings for him (maybe a little, but she can get over it because she thought his flirting meant something but hoped it didnt), but she sort of feels used now. Anyone clarify what the deal could have been? Should the friend confront him about it, like ask what that was about. Was he a player, he didnt have to himself initiate to flirt with Sara everytime and ruin the friendship, then get a gf and everything gets odd.