I think Eire's suggestion only complicates matters. It has been 8 years and presumably there has been no contact between mother and the biological father. Why drag another man into this who will have his own agenda and needs? Can noregret really continue to provide emotional support, act as a 'dad' to this child on the one hand, whilst saying with the other that he's not paying one red nickel for son's maintenance? I don't think that will wash. ANd if the biological dad did pay maintenance, he would presumably go for contact. Or he may say he wants nothing to do with the boy(he may be married himself?: Have a family of his own right now?) So a double rejection for the kid? Is this right stage in this young boy's life to add even more complications? I don't think so. Perhaps in a few years but right now, it seems that there is going to be enough turmoil without bringing another man into this.
The victim in this is both the father who feels, rightly, cuckolded, and this young boy. And without wanting to exonerate the wife, I can't imagine how stressful it must have been throughout this time to live a lie to both her son who she must love wtihout question, and her husband who presumably, she did love (if not, still does). Was it a one night stand? was it a full blown affair?
I feel for all three of you. Azurepheonix, your reply bought tears to my eyes. I have not met you but i feel proud of you!! I hope, noregrets, that as time passes and your anger starts to abate, you can be the man you no doubt are capable of being ,and remain as a dad to a son who loves you.