Universe: The Original Series - Prime!verse
It took them a long time to accept each other, and when they did it happened because they finally understood one another. They had both loved and lost. Then they realize that these losses would be nothing if they were to lose each other.
Jim and Spock become more to each other than Captain and First Officer after discussing why Jim allowed Edith Keeler to die in the past, and why Spock turned away from Zarabeth to leave her in the past, knowing that she would die. Had Edith lived, or had Spock stayed with Zarabeth, Kirk and Spock would never have met.
And that thought saddens both of them more than what they chose to allow instead.
Characters: Edith Keeler