He lost his father at a young age, saw his mother struggling with poverty, saw the society bad mouthing and men lusting his mother, the responsibility of giving his mother and sisters a better future. The only thing he loved and wanted in his entire life for himself was Sona and that too he had to sacrifice for the person who he owns his life to - his mother.
How harsh can it get???? Don't we all think that he deserves to be happy in life after what he has gone through and what he has done for the people around him. He did commit a grave mistake and he needs to repent for it. But not by getting Sona married to someone else. Dev definitely deserves a second chance and be happy forever.