Is this karma or biological coincidence?

I know a perfect karma tale. Quite long but I would abbreviate. A spinster had an affair with a married senior colleague at her workplace. About nine months after breaking up with her married man lover, along came a dazzling young man searching for his missing rib. One thing led to the other and then they started dating. Noticing the relationship was getting serious, her conscience prompted her to confess her past misdeeds to her bf. Of course it was a bitter pill to swallow for the young man but none the less decided to proceed with the relationship believing she had turned a new leaf. He then proposed and she joyeously accepted to marry him. Approximately a year into the matrimony, along came a bouncing baby boy. Instead of bringing joy to the family, his arrival became a source of huge suspicion by the father. Now here's the interesting part.
You see the man and his wife were both dark, tall and had moderate features. Guess what? The baby looked nothing like his parents. He came out with an emphasized fair skin, hairy and large pair of ears. A perfect contrast to his parents. Of course doubts crept into the mind of the dad and he immediately insisted on conducting a DNA test. The result proclaimed him the biological father to a degree of 99.999% accuracy. Now here comes the odd twist. One day whilst watching tv, the wife spots her erstwhile ex-married man lover, draws the attention of her husband to him and lo and behold the man bore a striking resemblance to their son. Similar skin complexion, similar shape of head, similar ear architecture and possibly similar build. A worried and baffled husband now leaves in perpetual doubt whether the boy he claims to be his son is actually his. Bearing in mind the striking semblence btw the boy and his wife's ex lover. Now my question is: Is this karma coming back to haunt the wife or just pure biological coincidence? And secondly how should the husband manage the emotional trauma of this predicament?