Hello!
I have an interviw this month as well.
It wasn't what we expected but now we have to deal with it.
If your relatioship its genuine its going to be easy, only thing you have to do its a lot of printing that's all
.
Bring everything what that asked for and that's it.
Proofs of your relationship the most important, not the ones you already sent along with your application but the ones after that...(for sure have to be something...hard tostay apart of your wife/husband...)
PS You should consider you very lucky becouse you are coming from India, I haven't seen such a fast VO as New Delhi, they give visas as the "bakers make bread.." piece of cake...so no worries!