Is my bfs female friend jealous?

It sounds to me as if she would like a bit more of his attention, for whatever reason. You started out right by going directly to your boyfriend and letting him know it bothered you. He gave you the basic assurance needed, but you two didn't quite finish the issue: what is *she* going through, and do you need to do anything about it? If she's simply missing the time she used to spend with him, the two of you will have to decide whether you've been slighting her as a friend. It's quite possible that she's just feeling left out of the friendship, and is returning to old times when she saw him more often.