Something that always works is to listen to your gut. I think that she might just be cheating on you if she is changing her ways and not doing it for your extra attention. Does she mention how she is going to look hot for you? or any comments like that?
honestly, listen to your gut. I dont think i have ever been cheated on nor have i cheated so i cant give any expert advice here. but i think your relationship is on the rocks. you can sit down and talk with her about EVERYTHIGN and try to start anew or just cut it now. good luck!