The reason Maan didn't want to name their relationship, because he didn't want her to be confined to the emotional framework that comes with christening their relationship.
He could call it friendship, but there is certainly attraction as well. So there is leeway for creating an internal conflict in her, when she is ready to acknowledge or wants to express her affections...even attraction physically . And the same restrain can come with different levels. Think about this: what if they go different ways after they find out it was only enjoyable until they were having coffee and nothing more? Calling it a relationship, will make this time count when it turns sour. Either ways its too soon to call it one, when they still have no idea about their backgrounds or personalities in entirety. For all you know, he could still be a serial killer...:)
The second question about directing all of one's love and affection towards one person...Well it comes into picture, when their attractions are acknowledged and matures enough to be called a relationship of some form. At the moment, they like each other enough to not mind spending around time around the other. I think its pretty embarrassing and ingenue of them to call it a relationship, (let alone approach this as a open relationship), when they have only really known each other for a few hours.
Don't you think?
<edit>
Oh!...the most important of all: its she who questions if Maan is proposing a open relationship. The update is all from Geet's POV, except for the last para.
I always give a double space when the POV changes. :)
99