There are at least two answers to this question, based on whether you want to know (1) what you're allowed to do or (2) what would be the best thing to do?

Assuming you are the innocent party which has been abandoned by your spouse, after you have made every reasonable effort to reconcile, you can claim that you have been abandoned. We would ask that a sufficient amount of time be given in order to demonstrate that the other has left them for good.

1 Cor 7:13-15
13 And a woman who has an unbelieving husband, and he consents to live with her, she must not send her husband away..  
15 Yet if the unbelieving one leaves, let him leave; the brother or the sister is not under bondage in such cases, but God has called us to peace.

However, a divorce might not be the best thing to do, even if the other seems to be irreconcilable. We are commanded to forgive one another (Matt 18:21-22) and God's will would be to restore the marriage if possible.