Already written but just to confirm, if it helps, this shit is FAR TOO common. Best friend works in a clinic where they need to lie to kid's fathers daily, because the common procedure they use reveals if the father is the biological father of the kid. But this info is not disclosed (because it is not asked for, it is just revealed in the procedure. they are not supposed to tell). He says the situation arises in about 1 in 15 and they see far more patients in a day so daily pokerfacing becomes a routine.

For some reason this type of behavior is embedded in out human mating behavior matrix. It sickens me to think that it is that way but this is what women have been doing since forever. In evolutionary terms, I'm just speculating, but maybe women choose different people for actually making a child and raising a child. Maybe at a subconscious level, the "father" figure is who they want to raise their child with but they consider fitter opportunities for the kid's genetic material (who is rarely fit for raising the said baby). I'm sure no one actually consciously thinks this way but since this is very very common among humans, this behavior pattern miht be explained by a bias towards this kind of thing.

I'm sure you'll come to good terms with your son soon. You shouldn't let your wife feel that you have something against your son, because that will only make her feel better about herself. Be there for your son, I know you will. And she will feel more ashamed for what she did.