Arnav's mysterious silence

Why is arnav not telling everybody( if not everybody then nani only ) what had he done to save his sister's marriage? Everybody including nani was shocked to see them in the kissing position bcz to them they have been married for 4/5 months now and to them they have been physically intimate as well bcz this is what arnav told them that it's a love marriage so now this apparent show of raging hormones on arnav's part is very absurd for them...it looks insensitive and down right selfish as well to them bcz they don't know the truth,i am not justifying them but from there point of view this is all they can see and percieve...unfortunately for Khushi she is paying the price for her husband's stupidity...Arnav should be man enough to own up his gravest mistake he has made regarding Khushi and do right by his wife for once.

I agree it's a daily soap and it runs on MUs but in this case they can keep hiding the truth from the whole family apart from nani bcz she is the only one who supports Khushi and respects her as well,why do they want to take away that support from Khushi as well?