I say do what's in your heart, but you gotta keep living. Sadly, if and when you do find her, she or the mom could then come after you for all those years of child support.
There is no easy answer.
Kudos to this hypothetical man for all the years of looking and caring.
If it were my kid and the ex took him, I would never stop looking. She was probably told so many lies if taken at the age she was, and she has the right to know the truth.
Best of luck.

a hen, of course

The longer you wait the harder it will be. Call him, set up a visit. Do it now. dont wait. the apology can wait until you see him. and telling him things in person will mean a lot more than a letter. I watched my husband let his son slip through his fingers, and I don't know if it can ever be repaired at this point. For your sake and for his, call him. Just being there will help the hurt some. And if he says no, or mom says no, give it a little time and try again. God bless you and good luck.