He is asking her to wear a Duppatta, NOT a Hijab, (big difference).. This makes me think he is asking Sara to wear the scarf/dupatta for cultural reasons and not religious ones...
If the husband was really religious, 1. - He would have married a Girl who already wore the Hijab and 2. - If she didn't, he would ask her to wear the Hijab (as oppossed to a scarf).. As the Hijab is a religious requirement whereas the scarf/dupatta is a cultural thing..
Sara, you need to sit him down and talk with him. He aint no mind reader and he won't know what you are feeling/thinking unless you tell him.. Once you've aired your concerns and you've listened to him, then the two of you need to come to some compromise TOGETHER.. But bare in mind that (as someone else said) he is not going to become less "religious" as a compromise to keep the peace..
At the end of the day, you agreed to marry a man from Pak, who was "religious".. You knew of, or had suspicions as to the nature of his personality, views and opinions.. It's not like anything he is doing, you didn't expect. You must have been prepared for this issue and knew it was inevitable..
(I will add this though.. the look on my Husbands face when I get ready and put on my Hijab is priceless... If I forget everything else, I will never forget the love and appreciation in his eyes.. and btw, I was wearing the hijab before we were married..)