I wouldn't have cheated on my wife to begin with so this won't happen to me.
Now if I foundnoutbtherebwas a kid from back before I was married...that would be really strange and I'm not really sure what I would do.
It sort of depends on how old the kid is and why they are trying to make contact with you.
This just happened to me this past November. Yes, it's very strange. Same situation, I didn't cheat and it was before my wife and I got together and had 4 kids of our own. Recently I found out I have a 21 year old daughter (22 in May), who also has a 1 yr old daughter of her own, my granddaughter. For simplicity's sake, in this response we'll call my new daughter's mother "Holly" (not her real name).
Most people always think of the child(ren) first, which is proper. I would too. I think it's human nature to automatically empathize or think of the "weakest" or most susceptible to danger or harm (whether physical or mental). I'm proof positive that it fucks the parent(s) up too.
Even though I never cheated, it still fucked my wife up, it was not easy for her to accept and deal with either. And despite my wife being the one person I should be able to confide in (about most anything), I feel wrong in having her be the sympathetic ear and person to try to help me cope with all of this. I don't want to hurt her anymore than she already is over this.
She met "Holly" and was instantly on guard and defensive over her, and felt threatened by her. Not completely because of what she did to me, but because of her looks. Won't lie, "Holly" hasn't aged a day, she's still smoking hot. I've tried and tried to reassure my wife she has nothing to be worried about, and I can see her lying to me when she says she believes me.
My kids all took the news differently, so there's another 4 sets of emotions I had to deal with. Jealousy, happiness, uncertainty, wariness, confusion... I saw it all. My wife and children are my "hot buttons". If you want to see someone go utterly savage, just fuck with my family and see what happens. And now, someone who has (apparently) contributed to the size of my family, is fucking with my family (unintentionally I suppose).
I'm still trying to deal with it. I know the 4 kids my wife and I had together, inside out. The good, the bad, their likes and dislikes, all the injuries and hard times they've suffered, all the significant milestones... and now here I have a daughter and a granddaughter which I really know nothing about (but I've been learning). All the little things, the characteristics of their individual personalities as they become... them.
When I first found out, I ran the gamut of emotions and analyzed all the possible scenarios. Now I think I'm more confused than when I first found out.
The only person I can talk to and learn about my daughter is "Holly" (and we never really had a relationship to start with). I'm of mixed emotions on how I'm supposed to be feeling about this woman. I did like her a lot back then, but it is what it is and she didn't want to be someone else's sidepiece (one of her friends told her I had a GF, which I didn't). Can't really fault her for that, only for not trying to find out the truth back then. On the other hand, I can't begin to tell you about all the awful things I'd like to do to this woman.
On the outside, I'm trying to play the normal, level-headed nice guy role with my new daughter and her mother. To show that despite whatever happened it does get better and responsibility and accountability is important in life. To show my daughter that she does matter to me and my family, and that she's now a part of it. My new daughter is absolutely thrilled I gave her something her mother never did... she always wanted siblings, and now boom! She's got two brothers and two sisters.
On the inside, I am absolutely incensed and hateful with "Holly". She took so much from me that I can never get back, despite being told of things and seeing pictures of moments I should've experienced at the time. What she took from our daughter. If I get mad, and rip into "Holly", I run the risk of pushing my new daughter away.
I'll be the first to admit, I'm not a perfect parent and I've made my share of mistakes as we've gone along, but in the larger scheme of things, I think I've been a pretty good father to my kids, and now I have a child that I was never given the opportunity to have the same effect or influence on.
I wasn't really a bad guy back then (at least not to friends, family and women), so I was really confused when trying to figure out why I was left in the dark and not given a chance. My friends joke about it a lot... "Well, at least you never had to pay child support!". I give zero fucks about the money, I would've happily paid whatever she wanted if it meant I got to know my daughter.
Am I "entitled" to answers? Yes, I think so. Had the roles been reversed, I would've been expected to answer for my actions and decisions. Does "Holly" have to answer to me? Nope, not a bit apparently.
If people think it's any easier for the parent(s) to deal with, I've got news for you.