I'm not sure what the point was - the thing is, throughout history mothers in a situation like this, where they have a child conceived from someone other than their partner, have kept quiet about this, and the child has grown up accepted as the son or daughter of the partner.
I think that is how it should be, because it has seemed likely in most cases to be the best solution for the child, and for the adult to be. And I think that probably still applies today, in spite of all the changes in society.
Honesty is a good thing. But there are other things which are more important.
Here are links to four songs involving (and impliocitly approving of) this deception, and I'm sure there are many more: