This was a relationship that went on as father and child for over fifteen years.
Methinks that this was more about the money for the current wife than doing the "noble" thing." Plus to cut out someone very important in his life so she could be #1. The shame of the matter is that this child is so close to the age of majority that cs is probably going to end soon anyway.
Tada! she thinks she won out. She's now #1 temporarily. However I think this is going to come back and bite her in the rear in the long run. This was truly a mean and vindictive thing to do--breakup a parent child relationship that had been established for years.
If a person establishes a parent/child relationship FULLY informed about whether they are the biopaprent, biological relationships would make no difference fifteen years later. Many of us could care less whether our child is or is not our biological child. Not being bioparent shouldn't "ruin a relationshp", nor is anyone but the lying biomom to blame for the fact that the biodad turns out to now be discovered to NOT be legal dad.
Just because they didn't know the truth, yet, doesn't mean it wasn't out there to be discovered. Kiddo might have had some blood work done, a medical test, or maybe a science project where blood types, or eye color and dominant/recessive genes were studied, and then, VOILA, Kiddo suddenly realizes it.
Bottom line is this: only the Mom knows everyone she has had sex with. She has to KNOW that multiple partners can mean multiple potential fathers, unless she's been living in a cave with no electricity, all her life. Regardless of when and how the TRUTH is discovered, the lie was created by her in the first place. It would get outed at some point, with or without the new wife.
It's no different than adoptive parents who lie to their child about bioparenatge. If the truth is always known, it is never an issue later. One should NEVER lie about bioparentage.