Why didn't they screw?

Maybe it is too late to re-start this, but here goes.
I don't know if Bella had a cinema release in Australia, but if it did I missed it and just caught up with the DVD in the local video store. I thought it was excellent.
It seems to me that the question that underlies many of the observations of those who didn't like the movie, or found it confusing or unresolved, is why didn't they screw? or why didn't they decide to spend their lives together? What made the movie a little special for me was that, somewhat against the tide - of movies, and life - the movie took the view that people - even healthy, physically attracive people - can find and value and support - and, yes, love - each other for a time without having to climb into bed. Not that there is anything wrong with sex, but, just occasionally, it is not quite the ticket.
Jose had spent a good part of his life unable to resolve his having caused the death of a child, and Nina had lost a large part of her childhood - or at least her teenage years mothering her mother. So he needed to save a child and she didn't need to mother one, at least not yet.
Why did he go after her at the restaurant? It was an act of kindness. And the fact that she was pregnant was simply serendipity. Or maybe kama - the kind of serendipity that seems often to come from an act of kindness.
The abortion scene was simply a future memory that didn't eventuate, but might have - a device that I have seen in a bunch of other movies.
I have views about the pro life/pro choice issue too, but enough for now.