Perhaps it is the greatest grief, after all, to be left on earth when another is gone.
There is no law that gods must be fair, Achilles,” Chiron said. “And perhaps it is the greater grief, after all, to be left on earth when another is gone. Do you think?
People are people, whatever age they're living in. The circumstances may have changed - we go to war with planes instead of chariots - but experiences of grief, longing, rage and love remain the same.
The very dull truth is that writing love scenes is the same as writing other scenes - your job is to be fully engaged in the character's experience. What does this mean to them? How are they changed by it, or not? I remember being a little nervous, as I am when writing any high-stakes, intense scene (death, sex, grief, joy).