'Character A's Past Bad Realtionship(s) Effect(s) Their Relationship With Character B' <-- Should this be 'Affects'? 'Effects' in this sentence would mean that the past bad relationship made their relationship with B come into being, where 'affects' means that the past bad relationship informs or makes changes to the A/B relationship.

English! It's the worst sometimes!

(Also "Relationship" appears to be misspelled in the tag)