Being in a relationship ends in one of two ways; breaking up or death. When you think about it like that, love really is doomed from the beginning yet we continue to nearly kill ourselves anyway just to taste it.
Just to put things in perspective: The Milky Way is so huge, it would take 100,000 light years to cross it. If we scaled our solar system down to the size of a quarter, the Sun would be a microscopic speck two soccer fields away from the nearest star. Source