I see what you're saying, but we really aren't talking about the same thing because the way you're using the term "love" is not the same way that I am. You're still talking about an emotion, I'm talking about a free act of the will.
Are you saying that our natural instinct is for self-preservation, and self-sacrifice only happens when our emotions cloud our judgement?
We might talk about it differently.
Ultimately, I think love is not really any different from any other emotion, its not free in any way. So talking about it, as if we have full control over it, I think is the wrong way to look at it. (If I understand what you mean when you say "free act of the will").
People don't choose who to love, a mother doesn't decide whether or not they want to love their child, and I think most "good" mothers would sacrifice themselves for their child. So if survival of the individual is the overall goal behind lifeforms, very important to point out that we are talking about individual, because survival as a species to me, is highly different, and doesn't come close to the emotional impact that individual survival has.
A good example of what I mean is, that if we imagine that we have an apocalyptic event on Earth and 99.8% of all humans die, you wont have people caring about the survival of the human race, they will think about survival from an egoistic point of view. So its not like you having survived and is standing there all alone, and then being extremely emotional about whether those in China made it or not, survival will be from your perspective, so you want to find other humans, because it does you good etc.
So if survival is highly individually, something must interfere with it, because we know that a mother or parent will in a lot of cases, sacrifice themself for their child and even other humans in general. But to me, I think its far more likely that a parent will sacrifice themself for their child than some random person. And to me, that is where love plays a huge part, because of the strong bond. But neither of the parents chose this bond, it just sort of happened, because that is how nature works.
In cases where we do not have love as such involved, but other emotions such as being able feel the pain, suffering or desperation of others, I think you will basically take a chance or risk assessment, which is based on your emotions, and if they are strong enough you will take the chance in order to try to save them even though you don't even know them, purely because you can relate to their situation and their emotions.
An example could be that you are walking near a lake during the winter and suddenly you see a child fall through the ice and is yelling for help and in a lot of desperation. You walking out there means that you are likely to fall through and die yourself, so why would you risk it, if its purely about survival? You don't know the child anyway, right?
But for some reason, you react to the child being desperate, scared and in pain. So you can either react with fear and simply be to afraid to go out there to help or you can make a quick judgement that you are willing to take the risk of dying in order to help this child, that you have no clue who is. Now if it were your own child, you would probably skip the judgement part and just go out there and try to help, your love for the child would most likely also highly reduce the fear of loosing your own life, because theirs are more important.
So in the end, love and emotions as I see it, is not really free, so talking about it as an act of freedom is the wrong way to look at it. love is simply an emotion, just like fear, sadness etc. So you might as well talk about the free act of sadness, in my opinion.