Anandi proposed bcoz of her promise to her mom. True. Shiv was very well aware of the situation. Anandi didn't pretend to love him or seduce him and get him married to her. She has been honest with her intention. Shiv is madly in love with her, so he agreed.
So if we see, Shiv is pretty clear about where he stands with her.
Now that Shiv & Anandi's stands are clear to each other, it's obvious that Anandi will not immediately jump in bed with him. She will take some time. From the way Shiv has been shown as a perceptive and sensitive person, he understands this too & that's why out of respect for Anandi he slept on the sofa. Anandi gracefully accepted his gesture & his care. She already knew why he slept on the sofa. So she didn't ask an intrusive, uncomfortable question like this in the morning.
Everything is how it would be when it's an arranged marriage with a twist.. If she sleeps with him for the sake of what all he has done for her, it would be an insult to his love. Its better to wait till the time both want to do it our of love.
Now the story is about how & when Anandi falls in love with him. Till now its been shown that she cares for him, respects the institution of marriage and respects Shiv himself highly. How has this much happened, bcoz of Shiv's behavior, his caring sensitive attitude, the way he gives her so much respect - everything that he has done so far.