Is this girl trying to get me mad at my boyfriend or steal my bf help?

so im dating this girls ex bf im not firends with her but they dated like for a year. me and him have been dating for like 3 months now and school just started his ex found out were dating and is like omg im so happy for you!!! like im really happy this is awesome and ive never been friends with her and now she wants to be like really good friends all of the sudden she wants to go out to lunch and hang out on the weekends and she ims me everyday and everyday she starts asking me a milliuon questions about my boyfriend and its getting reallly creepy this is the 3rd time she did it and shes like saying i hope it doesnt upset u me and him are still really close and talk alot. like wtf so i told my boyfriend and he said it wasnt true ive seen his texts before to like they dont talk he said there not even close anymore and that hes so sorry and **** im just confused what this girls up to what her motives are?