There is absolutely no way that Abha is going to tell her family about her and Karan's relationship, let alone marriage. She does not want to hurt her family by revealing the truth. Remember, in family matters, she is the dutiful, meek daughter of her strict father. She, unlike Karan, does not follow her heart and feelings. Karan is the one who is teaching her how to love.
Unfortunately, we'll have to grin and bear it until the apocalypse aka Abha and Sanskaar's wedding.
I absolutely hate it when girls or boys wait until the very last moment, after all the arrangements, to express their true feelings. It hurts so many other people too.