Hello,
1) If you have applied for mutually consented divorce and if your partner is backing off or is not agreeable to terms the petition can get dismissed as mutual consent forms the basis of the petition.
2) You will then have to move ahead with a separate petition for Divorce unilaterally.A contested divorce will take 3 to 4 years to be disposed of.
3) If the apartment is owned jointly you both are 50% owners and hence the shares are equal. As regards the loss you are incurring you can keep a record of the emis you are paying and when a final decision is arrived at these details will matter.
4) Alternately find a seller who will purchase the apartment with the loan pending and share the proceeds according to the monetary contribution of each. You need to have proofs to substantiate your contribution in purchasing the apartment so far.