I'm saying, cuckoldry is not traditional, or normal behavior, that lends itself towards building a strong nuclear family unit.
I read somewhere that over one in ten people have a father who's not their real father. Cuckoldry seems quite common but surreptitious.
I'm not sure I would call 10% common. And among those 10% there could be any number of children whose father died or just ran away, which would increase the likelihood of an adoptive father. And that's assuming that the one in ten figure is correct in the first place (which I wouldn't be surprised by because most people are impulsive twats that don't have zero self-control).