Love is a notion of the heart. However foolhardy a choice it may be, it's the one your heart decides.
Though still a choice.
True unabiding love may only occur once in a lifetime. For you have only one heart to give.
You may only love someone as much as you are capable of hating them.
There are such hazy lines between love and hate, pleasure and pain, rage and desire.
To truly love someone, a part of you must resent them for the power they have over you. The power to right all wrongs.
And the power to steal from you great amounts of joy.
A cynics view may be that you only give the most of oneself in unreciprocated love because it's human nature to want the most the thing you cannot have.
Though again...It is yet a choice.