seeking sanity

Is she addicted to the coke? Recreation and addiction are different. If she's an addict, and if there has been more than one affair, or if sex is involved in accessing the drugs, then the addiction needs to get dealt with before you'll get anywhere near the truth.

Ongoing affairs are addictive, too. Same pattern of lying, minimizing, blame shifting, furtiveness. There's a saying, "believe none of what you hear and only half of what you see" while she's in this mess.

Her actions will tell you more than her words. If she stay's home at night, is forthcoming with her whereabouts, takes steps to make amends and give you a measure of comfort and safety, takes responsibility for righting wrongs, you have hope.

More likely it will be a few days or weeks of effort on her part, then some justification to go back to how she was behaving.

I doubt marriage counselling will help much until she gets some individual counselling and figures out what the hell she is doing and why.