@guptill: I have a slightly different point of view than yours on why Manav took this decision.
I don't think he took this decision as he feels committed to Shravani.
If that had been the case then even though he would be marrying Shravani his behavior with Archu wud be of concern or guilt, not of anger.
I think Manav took this decision cos he thinks his relationship with Archana will never be the same again however much both of them love each other. The respect in the relationship is gone from his side. If there is respect but no love the relationship still has some hope, but relationship without respect is nothing. That is why he keeps saying that this relationshi has ended.
And he has reasons for that... he thinks Archana was party to Manjusha's scheming plan. He thinks Archana wanted to get rid of him (divorce papers). He thought Archu sent the mangalsutra back.
Today the love is very much there.... but he is suppressing it bcos it is impossible to live in the same room with the person you dont respect any more.
If I had been in Manav's place, I wouldn't marry Shravani but even I wouldn't have accepted Archu back.
But Manav is Manav, he thinks my relationship is over and out. My life is like a tissue paper, ultimately I'm going in the dustbin only, so at least someone else will wipe her tears with this tissue paper if I make this sacrifice.
Cos he knows he will never be able to move on in life without Archu, and cannot accept her back, so is ready to marry Shravani since it is a compromise anyway... even Shravani knows it and so there are no unfair expectations from both sides. This marriage is only a certificate for society to accept shravani back is what he thinks.