Should I Expose These Secrets To My Wife?

I am a fairly comfortable man financially and I run a thriving computer business. I am married, have kids and have had the occasional affair from time to time. However, some few months back I met this girl, who was then a newly appointed secretary in my friend’s office and I started what I thought would be a casual affair with her.
But I’m now completely infatuated with her. It was a surprise when she gave me one of the best s*x treat I’ve had in my life and s*x with her gets better and better...

I gave my wife my word that I wouldn’t have children outside our marriage. But I have invested so much cash and emotion in this girl that I feel I shouldn’t let another man enjoy the fruits of my labour, so to speak. She is keen on having my baby. 

What is stopping me really is my promise to my wife. Should I be tied to a promise I made years ago?

- A message from a married man to Aunty Bunmi. Below is her reply to the 'troubled' husband:

Dear Husband,
The fact that you think this particular affair is ‘hot’ makes a difference to the s*xual charge you feel with other women. As you must have discovered in all the affairs you’ve had since your marriage, an illicit liaison is much more exciting than real life!

Far be it that I should be the one to help you decide what to do, but if you’re prepared for a double life, endless conflicts of time and loyalties and risking your marriage, you can have your love-child. But when reality kicks in, you’ll discover it’s not such an exciting prospect.

This fever will definitely bum itself out. Since you are a philanderer, the earlier you tried to stop, the less conflict you would have, enjoy marriage with your wife.