Aaah. Sparsh - fantastic choice of title. The word itself has a soothing, magical touch to it and its the perfect name for this beautiful story.
I read all 4 parts in one go, but - should have waited till you complete the story. That would be such a treat.
Loved the tale - and the twists and turns you are bringing into it. You write beautifully - that's a given, so i am just enjoying the lovely tale you are weaving. I can totally visualize what you have written, the expressions, the pathos, the impishness, the caring love and concern...the only "sad" part for me is that the other Arti and Aman are no more :(. But perhaps they will appear in some flashback?
Think about writing a novel - you will have to flesh out some of these characters and their back-grounds more. Which means we readers get more to read (totally selfish request on my part - but really, i mean it).