Janvi had No idea about
Omkara is a drug addict but
she was aware of the affair
... Here my Thought..
Tej affair Started . may be janvi Wanted to hide from omkara but Omkara got to know or he was doing the same..
Then he Started to take the drugs. it's Revealed to Shivaay and There will be incident took place Omkara Ne Shivaay ko promise Kiya (joh Baad me dikhayenge)
Janvi ko apne Bachoo ke liye Secure life style chahiyen..
After all he is also daughter-in-law of the family ...
And When She found out About Omkara's Dark Past he thought Just by staying with her brothers can only save him And he will not break the promise so Janvi decided that she will not divorce her husband...