It is an unconditional love that does not require the other party to return anything. My children could do anything (ANYTHING) and I would still love them--I might not understand it, I might not condone it, but nothing would make me stop loving them. A partner is just that; a partner that one exchanges energies with. A marriage is a contract--you do this, I do that--blah blah blah. I have yet to meet the man whom I would love unconditionally (especially as a marriage partner) and expect nothing in return.
This hits the nail on the head for me. There are many things a spouse, partner, etc, could do that would totally destroy your love for them. But I will ALWAYS love my son. I won't always condone his actions, I am not blind to his faults (although he's only 5 so they are few right now ), but I WILL ALWAYS LOVE HIM. Done. Finished. No questions asked.
I have fallen out of love with other people, and I'm pretty sure I no longer love my husband (long story, but it's his fault). That will never apply to my son.
I don't necessarily think this only applies to mothers and their children, I know some men who have the same no holds barred, balls to the wall love for their children. I think it's great.
Happyout - born to be a mother