There is only one way to be in love with fate, and that is to refuse to be its victim. In other words, to challenge it at every turn. Thus, amor fati is the most passionate of loves, based in constant conflict. What has to be understood though is that fate as a predetermined course of events does not exist. At every moment, wherever I may find myself, I have a choice, at the very least, the choice to call it quits for good, to declare the game is over. But this choice always occurs (even within the most ideal of situations) within conditions that are not completely of my choosing.
The complexity of natural relationships is one level of these conditions. It is not too difficult to see the options that exist within the conditions on this level. In fact, challenging these conditions always has the feel of an adventure, and among the highly civilized, becomes a form of recreation.
But social reality takes things to another level. Here there is the paradox of a set of conditions that exists only because of our activity, and yet that also determines that activity, creating what appears to be an inescapable cycle. It is precisely in this area, where our own alienated activity determines our choices, that fate begins to appear to be a predetermined course of events. Even though every single thread in the social web is an activity carried out by an individual in relationship with other individuals, the complexity and vastness of the web can give this activity a mechanical appearance, as if there was some huge loom, beyond our control, actually weaving the web. In earlier times (and still today among those who choose to embrace the simplicity of stupidity), this imaginary loom was called God or the gods (in ancient Greece, it was imagined as three goddesses weaving cloth). Now it may be called History, the Forces of Production, Class Struggle, Progress,... any number of abstractions to distract us from the responsibility of our own concrete everyday activity in creating these conditions.
Amor fati, the passionate love of fate, in such a context, takes on the form of rebellion against the existing social reality. If social reality seems set, if I am forced to create my life in conditions not of my choosing, I will throw out my challenge to fate by striving perpetually to create my life against these conditions insofar as I am able. No doubt, social reality will perpetually throw up new walls in the face of my rebellion. External walls (more and more forms of social control) and internal walls (more and more aspects of my own repression coming out from the depths of my mind). But for the lover of fate, these are not defeats, but new challenges to be faced and embraced, new conflicts heightening the passion of life.
Philosophers can bicker all they want over the question of determinism versus free will. What matters to me is the lived battle between the conditions that have been imposed on my life and my creative will.