That's the problem. Both agreed to those marriages. They took the vows and agreed to the commitment but neither are taking their marriage seriously. I'll give it to prerna that at least she tried for a little before basu started interfering but even with basu around Prerna should have control over herself and draw the line. Bajaj is now in love with prerna and Komolika is in love with Basu. Like Bajaj said you want to prove me a villain. That's a direct line to those who call him a villain when he isn't. Bajaj wouldn't have to do what he did if Basu would've stopped bothering him, Even if Prerna told Basu the truth he wouldn't have stopped. Today episode was an example of that. Even after knowing the truth he still is bothering bajaj.
He wont stop anytime soon.
He needs to get a shock regarding pregnancy. Only then he will back off.