Asha is more selfish than Ashish in my point of view. When Ashish tried to tell her the facts which she would have to suffer in near future if they come together she just wanted to be with him no matter how she had to live.
If she was pregnant and she didn't want to blackmail Ashish she could have use another ways so that she would not have mess up her kids life. Again she is bringing another child to mess up things more.
Ashish knew his mother would never accept this relationship but she wanted him at any cost and in my pov such woman set a bad example for society and encourage wrong things. And now she is getting more selfish by planning another kid.
Coming to Ashish he just did a blunder by not telling it to his mother eleven years ago. He should have dared to do that so that the things never went out of hands. One more mistake he is doing that he should have told the whole truth to Neela at least she would never want a guy who is already married and have two kids.