Married in temple but pictures lost now girl wants to marry again

Sir/madum. I am from karnataka MYSORE. Me and my girlfriend both are engaged in love since 6years. And we had a good matured love in the mentioned period. Even we got married before a year in the presence of a small temple that to knowing only to both of us. And few photos were taken at the marriage time but i have lost that with my file folder while travelling in some area. And had a physicall relation ship too since 4 years. Now i just having the photos which we both have taken in our mobile phones when we were meeting. And i have her hand written love letters, and alos i do have whatsapp chat history of one year. But now she is going to engage with another guy. So please i request the advocates to guide me. What exact i can do by leagal means. And how to file a suit agains her. And what are the proceduers. And We got married in a temple. And we took photos of our marriage also in a friend cell phone. But my friend has lost that phone before 6 month. Now what is the leagal aspects