This is supposed to happen when you break up a perfectly happy couple.
Bajaj blackmailed Prerna into marrying her. She only married him because she wanted to save Anurag. She herself said that Anurag is her first priority. So of course she will go to him first. Also She always supported Bajaj when she thought he was right. I think no one should expect more than this from her.
It is true that there are millions of girl who would be a better choice to be Kucki's mother. Not because Prerna is a bad mother but because she was someone else's wife and was pregnant with her husband's child (Ya that's right Husband, NOT ex-lover, HUSBAND). Bajaj could have eeaasiilyy found a girl who was good mother, interested in him and most importantly was not someone else's wife. Tanvi would have been a better choice.
Bajaj's cunning character was revealed in the very beginning. He may be hooooot (☺️) but he is cunning. So please don't say that his character is butchered. He is just the male Version of Maya from Beyhadh (ironic but true. Only KaJen fans will understand). She was this great personality who planned her every step. But she also lost her mind and reacted the way she wasn't supposed to in some situations. Same thing is happening with Bajaj.
PS: What is the deal with Prerna's pregnancy. She found out that she's pregnant somewhere around February. So this must be her 8th month. Why is she so slim then? Is she like going to come out from pool one day with her pregnant belly like Pishachini from Diviya-Drishti??? 🤣