One thing is for sure that Dev will now never hurt Sonakshi. He has already done that mistake twice before unintentionally (under the influence of Ishwari) and faced the consequences. He is a changed man now. A man who is still the provider of the family but lives life at his own terms and with a I don't give a damn attitude. He cannot be manipulated by anyone including Ishwari. Deep inside Dev knows that what he and entire Dixit family did to Sonakshi was entirely wrong and so he felt guilty and himself freed her from all the sufferings with his harsh words so that she can easily move ahead in life and indirectly motivated her to be a winner in life.
After the whole prenuptial truth come out, Dev realized that his mother is no God. He then instantly chose Sona over Dixit family and was trying to make Sona understand his decision but she by then had fully lost trust in him and bluntly ended their relationship. As soon as Dev heard those words, something broke inside him. The two most important women in his life were over - one backstabbed him and other mistrusted him. That was enough for him to lose faith in all relationships.
Dev's only weakness or fault was always his blind love for his mother which is now shattered. No one can deny that Dev always had a golden heart. He always was and will always be one of a kind - a person who can go to any extent for his loved ones. So now that he is a man who takes his own decisions and a firm human being who cannot be manipulated ; Dev will surely immerge as a more nicer person which will lead to his true redemption.
I do not buy the theory of him harming Sona or snatching away Soha. Deep inside I have a strong feeling that Dev surely will have a hidden part in Sona's success. He may seem negative now but in long run he will surely immerge as a winner. A man who will win his wife back with dignity and give her all the respect she deserves.