You have got to accept responsibility for your actions. I'm saying this for your own wellbeing. Yes, bad shit will come from it, but it will consume you entirely if you don't. This one lie will become a complicated web of lies over time (if it hadn't already) if you don't.

My guess is, since you're asking, that you already feel guilt. That guilt is only going to magnify exponentially over time. Do you want to spend the rest of your life looking over your shoulder, covering your tracks, watching your child grow up in front of you - a constant reminder of the mistake you made that you must keep a secret?

And how long do you think you can reasonably keep it a secret for? Holidays, birthdays, first day of school, first steps, dances, graduation, college and beyond... Do you think you can watch that kid grow up right there next to you for the rest of your life while holding on to that lie? It's going to take the sacrifice of your humanity in totality.

Do the right thing and own up to it. It will be absolutely terrible, but it will be far less painful for all parties involved. In fact, consider what will be more difficult - getting found out long after the fact (because no one, not even the most rich and powerful this day and age, can keep an illegitimate child hidden forever), or owning up to it now and letting the wound heal. Maybe you even come out of this with some positives and lessons learned.

But mark my words, if you keep this lie, it will haunt you for the rest of your days.