What's wrong with her?
I use to be a smoker. A pack a day(before I met hubby). I didn't want my h to know, so I quit and took up running. Let me tell you, there's no possible way that she's doing a cardio workout and smoking. Especially if its up to 2 packs a day.
You may want to investigate a bit. Her behavior are classic signs of cheating. Don't be in denial or overlook this. The red flags are right there in front of you. Her improving her looks, massive amount of money spent, out late, increased going out, "girls night only"(yeah right, I don't believe her), ect.... These are huge indications there's another man(or woman) she's involved with.