I as most of us think Shaan moving out would have been better than the life trio are living right now. And Astha as mentioned many times always wanted the same. For Shaan to support her when she needed him the most.
The main problem is whatever Shaan chose Or whatever he was forced to choose, he was never at peace with that. He let his wife go physically but her thoughts never left him. He got his son with him but was not present for him. He grew bitter towards his family and took help in alcohol. His action affected life of his son and wife too. So I think trying to tackle problem named Sabharwals would have been better than surrendering to the situation.