I guess I've always kind of felt the opposite about loving-your-children vs. loving-a-lover. It's the same as what you say, I guess: a lover is chosen and a child is given. But to hear many parents talk, the second that child is given the love is instant and unconditional and doesn't happen for any other reason than that he's your child, and no matter what happens, that love will always be there. With a lover, you can always choose to walk away (of course a parent can choose that too but it's a little rarer).

But eh, I have no real experience in either, so I'm talking out of my ass.

I also don't believe that a first love is always the strongest or the best or the most important. I think it's something that IS important and you'll always remember it and it'll always be unique in your mind, but as someone who had a pretty crappy experience for first love I certainly hope there's something better out there for me.