Obviously sai virat the eternal lovers will reunite.
Let's say they r living with their kids happily post reunion. But virat sees pakhi trying to commit suicide by saying she doesn't have family. What is the guarantee that virat won't leave sai and kids for pakhi again?
In kd we can confidently say emon will lead happy life post reunion. Because she was wholeheartedly & genuinely accepted by rono family, rono was loyal to her for many years, rk doesn't live in that house. And rono learned his lesson for his actions in shruti track that he did many things to win back emon so we can be sure he won't repeat such mistakes.
But sai?
Virat's family treats her like shit, virat doesn't treat her like human, he can flip anytime. There is no guarantee that her daughter won't face abuse since chavans r obsessed with chirag.
It's just hypothetical question.