What does she want? She gave me her number and later I find out she's married!

I met this girl at a hair salon, she gave a hair cut. She’s very nice and sweet, our conversation didn’t stop for the whole time. At the end, I asked her if she’d mind going out, she turned her face and smiled and responded “TONIGHT?” I said not tonight, how about you give your number and we’ll text? and she agreed. Now I found her facebook profile and guess what?! She’s married and has a son!! This confuses me a lot since I never went out with a married girl.

My question,
1) What does she want from me?
2) Why would she give me her number if she’s married to some else?
3) What should I do about it?

Thank you and have a great day!