In India, being separated from your spouse for an extended time does not automatically lead to divorce. Even if you have been living apart for 7 years or more, you still need to go through the legal process of obtaining a divorce decree to formally end the marriage.
Simply separating from your partner, no matter for how long, does not dissolve the marital bond and allow you to legally marry someone else. You are still considered married in the eyes of the law.
To get divorced after prolonged separation, you have to file a divorce petition in family court citing your long separation as grounds. Most common grounds used in such cases are desertion and irretrievable breakdown of marriage. You have to furnish proof that you and your spouse have been living apart for the specified separation period.
If it has been 3 years of non-cohabitation, the court may pass a decree of divorce on grounds of desertion or abandonment. But most courts require at least 7 years of continuous separation before accepting irretrievable breakdown as grounds for dissolving the marriage.
Separated spouses sometimes start living with new partners without officially getting divorced. But this puts them at legal risk. If evidence of their live-in relationship surfaces, the legally wedded spouse can file adultery charges against them.
Bigamy laws also come into play if you remarry without divorcing your previous spouse. Any subsequent marriage is considered invalid and illegal till divorce is obtained. This can lead to criminal charges and complications.
The only exception is if your spouse is proven dead or presumed dead as per law. If 7 continuous years have passed since your spouse went missing without any news, you can obtain a death certificate and legally remarry.
To conclude, however many years you may have separated from your partner, the marriage is legally binding until you obtain a divorce decree from court. Physical separation cannot override the legal status of marriage. It is advisable to file for divorce after being separated for an extended period so you can legally move ahead with a new relationship if you wish to.