I too thought about it, and was wondering why she cannot come to terms with Virat and his feelings.
First, as @shristhi mentioned, absence of Samrat and Sai gave her some hope. She might be thinking that they both might not come back, she is sure she is not ready to move on, and believes Virat will not move on from Sai either (After reading his love for Sai in yesterday's confrontation). So it is okay for her if they both are stuck like this in a limbo 🤔. She also has hope that Virat might break after some time (may be years) and elders are anyways there to push them into a relationship. :).
Man that is the saddest thing to expect someone to be in limbo because you have one-sided feelings for them. Also, would any woman want to be in a relationship with a man who not only doesn't desire her, but is disgusted by her? Sai was ready to be in that relationship when Virat didn't desire her, but he respected her and cared for her, also, she had no other choice. In Pakhi's case she is married and has parents who will do anything for her.
As for as her character is concerned, I dont know what you call them. I call it stupidity to waste your life over a guy who doesnt reciprocate same feelings and who looks down upon you. These kind of people not only ruin themselves but also pose problems for good natured people around them. Because any one who has kind nature and related to them will feel bad for her situation. I am sure this is what is going to happen, she is going to get a lot of sympathy from everyone in the house. All her mistakes and vileness will be forgiven easily. So she will go ahead and up her game. When Sai comes back, she will be doubly manipulative. If she cannot stay with Virat, she will makes sure they both dont live happily. So she has lot of purpose by staying the way she is.
I truly hope her vileness is not forgiven. For the story she will still end up liviing in Chavan Nivas, but she should be shown her place and kept an eye on. I too think, she will act crazier when Sai comes back, but I hope Virat is on Sai's side and doesn't give in to PP's drama ever again, otherwise, there is no point in Sai coming back to the pagalkhana.
In real life, thats when parents or elders or doctors come in to help her 😲
And in real life, Virat and Sai would move out of the house!
This is not only a TV show, but ITV show, so forget any closeness to reality! They have their own bubble and they live in that universe. My surprise is we as audience accept these BS!!!