Najma broke up with him - that's on her. I don't believe in the idea that a man should try and fight for someone who told him they were done. When women do it they have no self-respect and I believe that's true for men too.
With regards to Tanveer - he had a one night stand - so what! Most people, today, don't just have one sexual partner and you are definitely not obligated to a person you have slept with. Also, why are we so sure that Tanveer was telling the truth with regards to the baby being his? There is no proof either way. And until we know for sure I won't judge him for his behavior with BR.
Now, with regards to Nikhat - he sure has wronged her but he never took undue advantage of her. He tried, for her sake, to love her and he was kind to her.
At the end of the day Imran is a weak and emotionally abused man which is a direct consequence of having been brought up with a mother like Haseena. It's not as easy as saying oh he had bad parents but he should move on. Life doesn't work like that. The way we are brought up and are cared for as children has a direct relation to how we are as adults and right now this is who Imran is. He is not a bad person - just weak and looking for love and acceptance.
Asad was a judgmental jackass as a result of his childhood, Ayaan a callous and irresponsible idiot and Zoya an emotionally wrecked person. Imran is in exactly the same way a product of his environment. We sympathize with our leads but they are no better or worse.
I agree that people's upbringing doesn't justify their attitudes or behavior but it does make them sympathetic characters and while I did believe he was a colossal jackass,before, I am open to seeing if he can in fact redeem himself. As MKI pointed out in her Extra Notes : it will have to be at the scale of Dev's redemption but it can be done. If a man who fake married, slept, got Geet preggers and then abandoned her can be redeemed why is Imran so irredeemable?