Why is my ex Gf Doing this?

we broke up like 2 months ago, we still in touch, but not like we used to, a month back she used to call me and text me pretty much every day, and we still hang out and stuff like that, but now that she saw that i been talking to my other friends ( which are girls) she came up with this thing that she has a new Bf, i know is totally b.s because 1 week back, i didnt text her or call her or whatever bcause i tought that we were over since she didnt wanna talk to me, a week ped and she text me back saying hi, the same day she texted me, she told me she had bf, i said if they still together and then she said no, so then i asked her whats shes been doing during that week and she said shes been chillin with her bf like 2 days ago on that same week,,,in other words, shes trying to make me jealous by saying she has another Bf, this is gonna sound pretty stupid and nerdy,but when she was with me she putted her self in a relationship on fb and all that,and now that shes suppsoe to be with him she doesnt do that,,,she calls me sometimes to hang out and stuff like that..shes confusing the hell outta me...WHY IS SHE DOING THIS??