Marriage affidavit required for Singapore tourist visa if no marriage certificate and different surnames?

Hi everyone,

My spouse and I are applying for a Singapore tourist visa from India for March 2026. We got married in 2023 but we do not have a marriage certificate or marriage license. Also, our surnames are different in our passports.

Our travel agent is asking us to submit a marriage affidavit stating that we are legally married and living together as husband and wife.

I wanted to understand from others who have applied before, is it mandatory to get the affidavit for visa?

Any insights would be really helpful.