More importantz that's the cuz of whole situation, no one is more important than anyone i mean you can't choose between your brother or father or mother and lover so why choose between friend and lover. I think itz more complicated than that and definitely i don't have the brains to put a finger on that.
The love for a parent is different to that of a lover or spouse,the love of a lover/spouse is romantic thus different from a friend,parent or child. And the love of a child is parental thus different again,so if I was put in a situation of having to choose; the child would be first.lover second followed by parents and a friend would be last. Therefore,love is categorized-ie, I love my child more than my partner etc....
It's true in its own way but why would you need to choose when they are both extremely important if someone says to choose one of them then they are at the wrong
Now do you get it?! One is your girlfriend and the other is your friend,it's not rocket science! Who is more important?!