Even I was wondering the same, it totally didn't make sense. But thinking about it, maybe what they were trying to say were two points.
1. After marriage all of Omkara's property goes to his wife (where Svetlana failed to mention her name, as it was a prenup about Omkara's and her wedding)
2. If Omkara fails to marry Svetlana, all of his wealth would go to Svetlana.
So, now we look it from legal point of view, Omkara is already married (at the time of signing the prenup), so all of his wealth is no longer his, it now belongs to his wife, Gauri (according to Svetlana's prenup.)
So right now, Omkara is a man with no property or money. Now that he has failed to marry Svetlana, all his money and property will go to Svetlana but due to her own prenup, Omkara is a penniless man. Which ends up with her not getting anything, and Gauri getting everything including the man, and Omkara not in any legal mess.