Well I'll wiggle my way in between you two
I will do anything and everything for those that I love. Fight, die, give up everything and do anything to keep them, well, happy and safe.
As for strangers, I have a general sense of respect, but if they are after what I want I will compete and compete hard. At that point I'm looking out for me and mine. You can worry about you and yours.
The only exception to these rules are if the cost vs benefit are way out of balance. For instance I once helped an old man who had fallen in the middle of a busy busy street to the curb and called the police. But it cost me little physical effort and a little bit of time to possibly save his life. Conversely I wouldn't kill someone to get my wife a candy bar.
But if all else is equal, I always look out for those closest to me first, foremost and always.