Fatalism has gotten a bad rap in our lexicon. Literally it suggests the belief that events are predetermined. All events - good and bad. But since we all like to believe in free will, fatalism has come to be identified with the sense that bad things will happen.
Romantic fatalism then is the looming predestination of your relationship to crash and burn. Nothing lasts especially not love. All less than interesting from a Harlequin romance point of view but not my point.
Romantic fatalism also refers to the sense of self-righteousness that comes over some people when they take on a support role to the fatally ill. I encountered this strange mindset back in the late 80s when I was heavily involved in the AIDS epidemic in Los Angeles. Some people seemed to glow with pride while helping a dying friend or relative. I don't really want to complain or castigate because romantic fatalism swells the pool of potential volunteers to support those with terminal diagnoses. I simply marvel at the seemingly reverse reaction to making a voluntary commitment to be with the dying.
Personally I never got any sense of 'lift' or 'joy' from my participation in the care of several AIDS patients. I struggled as did many with the random fatal virus striking down our family and friends. I wonder if a sense of romantic fatalism supports some of those medical professionals who work in hospice, if so then let it be. Such individuals have my greatest respect for their daily commitment to terminal patients.
For me I will continue to grapple with romance and fatalism as well as romantic fatalism.