Everyone throughout the galaxy know of Jim and Spock, they're extremely famous, so it's pretty common knowledge that they're bonded (even with all the completely ridiculous-and some even disturbing- rumors). They've made quite a few enemy's who would want to take advantage of that bond to get rid of them both.
What I want is an enemy of theirs to find a way to turn their bond against them. How they go about it is your business (but I do have a scene in my head where Kirk and Spock go down in front of a crowd simultaneously (screaming in agony clutching their heads? Just fainting?) if you include that then I would love you!) Maybe it affects all bonded Vulcans and their bondmates?
I would prefer if its in the Abramsverse and include Spock Prime and Sarek, but it's not necessary