I agree with what you are saying mitts
However, ever since the beginning of the serial, I have always said one thing. Manav's biggest fault is that he tries to keep everyone happy at one time. You remember the fake necklace issue with savita na? At that time, he tried to keep archu, savita and sulochana all happy at the same time. In all this he suffered, cos he was called a wimp, a weak person, etc, etc. and had to work overtime to pay off for the loan he had taken for the necklace.
Today again, things are going that way. He knows things have gone too far so he cannot go back. Shravani wud abort sachin's akhri nishani, savita wud never forgive him, the little happiness his family cud get back after's sachin's death will go. So he sticks to his decision of marrying shravani. But then what about Archu? how will she be happy? So he decides that he will make her hate him so that she can move on in life with someone else after the divorce.. (but we know that is never going to happen)... for this matter he does not defend her when Savita badmouthes her and behaves coldly with her, and in all this HE is the one dying within. He is the one who is called weak, selfish etc etc.
My point is... this attitude is wrong, First of all, you cannot keep everyone happy all at once. In life, you have to take some strong decisions in which you have to take one side. Maybe we will see Manav realising this in the future episodes. Secondly, the decision he has taken, of keeping peace in everyone's lives... does not guarantee happiness to anyone... he is taking responsibility of the child but shravani won't be happy, he is thinking that archu will move on without him, but that is far-off thinking, and the way he is handling things right now ("Mera dil rota hai jab Aai Archu se kuch kehti hai aur main kuch keh nahi sekta"... filling sindoor in shravani's maang without will and feeling horribly guilty later... not sharing his feelings with anyone in the family...not even his dad) I feel Manav shows tremendous signs of going under clinical depression. (So does Archu... if these horrible things continue.. )
Archu and Manav are both selfless... no doubt and we love them for it, but I dont want him to do it at the cost of his wife. Right now he is assuming that she will move on in life if he makes her hate him... (maybe cos once at a time people had told him her marriage was fixed to satish)... but he needs to realise that this is NEVER going to happen, and so his selflessness will give his wife nothing except loneliness
I will believe in the ArMan love story again if Manav takes the decision of backing of from the marriage for Archana's sake... blasts his Aai for some matter of Archana.. takes responsibilty of his mistakes...apologizes to the whole Karanjkar family and also to Archana.
DISCLAIMER: This was not Manav's defence. At least I don't think so. Only my own views of what I think is the problem with Manav.