Loss on Housing Property

Both husband and wife are owners of the house(flat) and the loan  is also availed by both(co-borrowers).  Whether, the Principal reapyment under section 80c to be approinted between them 50:50?  In case  any one of the already reached RS.1,00,000/- under section 80c without the repayment of housing loan(principal), whether the second one can claim the entire amount  after getting a certificate from the first one that he/she not availing this benefit?  Is it legally tenable.  It is only for the principal, but the interest is divided 50:50.