Please Advice Me : My !8+ yr old House Girl Is Tempting Me – What Should I Do?

I’m a pastor, but I also work as a civil servant. I would have loved to write further about where I live, but for the same reason why I can’t mention my name, I can’t tell you where I’m writing from. This young lady was brought to my house by my wife sometimes in 2010, and had just completed her secondary education last year.
She is supposed to pick up a form for her higher education because she is related to my wife; distant relation, sort of. Frankly, she has been very good, and has been taking care of my only daughter since my wife put to bed late last year. Her presence is a big relief to me and wife because we are both very busy people. My wife works with a bank, and sometimes come home around 8-9pm. Lately, this young girl has summoned courage to seduce me; to be sincere, she is tempting me