there relationship is very mental they don't really have 2 touch o talk its like they can read eachothers mind haha when jasper was with maria he thought he diden't diserve happyness o amor 4 what he did so when alice came around he diden't care about enything but her he wants 2 make her happy and protect her the same goes 4 alice they never fight if they do i bet its because jaspers being 2 potective (over protective fool) lol
i think taht alice and jasper have an unbreakable relationship. in the libros and cine u rarely see them apart. if tu do, well of course alice is trying to save bella and keeping it from jasper so he wont worry. i also know for a fact that jasper is over protective of her.
I think that they dont need to have a physical relationship they know exactly how each other feel and what there thinking (most the time)because there so attuned to each other. Jasper coming from the life he did, not thinking he deserved happiness, stumbled across alice who had been watching him for god know how long, and cares about nothing other than that she is happy and safe. Then Alice who has lived alone for ages after being abandon when she was changed.They need each other and each one of them plays a vital part in there relationship. Alice and Jasper being my favourite couple and all. But I didn't really understand the question.