Anurag and Taani are close friends (forget about the gender issue, since they belong to the 21st century). Anurag has spend 10 yrs in US, and there it is normal to have a close friend between a male and female and yet not think of marriage relationship. That's from where Anurag comes, and that's his modern way of thinking at age 24.
I see that atleast in the near future Anurag will see Taani as a close dear friend for whom he will selflessly do everything "A friend in need is a freind in deed". The possibility of Anurag marrying Taani may remain slim now and may be in the near future- if we think this is the 21st century.
Ofcourse, for Taani it is different (being raised in Indian tradition)- she believes on her childhood marriage. Maybe if the childhood marriage would not have taken place Taani may have also thought like Anurag.
Taani being a strong character will (I think ) come into terms with Anurag as a close friend, and will set him free emotionally (atleast on the outside), because she only wants Anurag's happiness. It will ofcourse be a big blow for her at a young age (23yrs), but she will eventually move on and concentrate on her career of singing. Circumstances may also force her to marry Shubodh Basu and become Taani Basu, and move out of Anurag's life ,who may be very happy with Nupur has his life partner.
'A Friend in Need is a Friend Deed' - Ofcourse when years after Anurag is in trouble, and no one is around him - he lands up in an asylum (for whatever reason) - he will think of his only closest friend (who was always there , deep in his subconscious mind). That's when the FRIEND - Taani Basu will come in the rescue.
I guess she will always remain as a close friend, dedicated to ' A Friend in Need', selflessly with nothing to receive in return.