Go buy DB/Div Remedy and give them a read. Also check out Not Just Friends. All very good resources.
W's friendship (!?) is inappropriate even without it being physical. At this point in time, just focus on yourself and drawing her back to you with positive behavior and love. There will be time to talk about her possible A. Some people confront right away (me!) and some wait (read SueS). You will do what feels right.
She might get mad that you snooped, but she will get over it.
Keep reading situations here, post on other threads so people get to know you. Good luck.
