If Ovi had received some right advice (instead of everything being brushed under the rug by the so called adults), she would have at least pretended to be understanding and patient of Arjun. The only time Arjun went looking for Purvi was the day after the wedding, that was understandable. He had been punched in his guts by both girls, one cannot expect him to recover overnight from such a beating. After that, every encounter between them was a chance happening, we the audience know that though Ovi chooses to believe otherwise. And please, do not use the word souten, it sounds so ugly and does not apply in this situation.
You are right, one cannot give help to one who is not ready to receive it. But Ovi aggravated the situation instead of easing it for Arjun, for them.
Even now, if Ovi wants Arjun badly enough, knowing that he wants his child, if she takes care of herself and the baby, she can salvage the situation. Arjun is not evil, he will grow to love the mother of his child. Ovi wanted Arjun at all costs even knowing he didn't love her and loved another, so how can she now demand that he love her solely for her, not even for their baby's sake? Wanting that is okay, demanding that raucously is not.
Ovi cannot change the equation at the drop of a hat, she went into marriage eagerly, willingly, and with eyes open. If she is patient and smart, she can still have Arjun and his heart. Yes, it will happen in time, he will grow to love her for herself once they bond over their shared life, their baby. She needs to concentrate on him, their baby and their life, not brood over her insecurities. Her scheming has paid off, she has landed the man, she needs to change tactics, play sweet to get him for keeps.