There should be a cheat to remove sentiments.
Truth be told, two people having a romantic relationship isn't enough reason to even trigger a betrayal sentiment, non-committed people make out all the time.
Basically if they are not married or even a girlfriend/boyfriend they have not been betrayed and shouldn't get that sentiment just because they like each other a lot (high romance bars)...
but regardless it definitely shouldn't happen with the Player Trait.
There are cheats...
modifyrelationship firstname lastname firstname2 lastname2 100 (Sentiment Tag)
if you want to take away a sentiment put -100 instead of 100
– sentimentTrack_Adoring_LT_lifesaver
– Awed by Lifesaving Hero
– This Sim was saved from the clutches of death by another Sim.
– sentimentTrack_Adoring_ST_impressed
– Impressed
– Impressed by the other sim
– sentimentTrack_Bitter_LT_cheating
– Betrayed by Cheating
– Cheating soured this Sim’s feelings about another, and being around them may bring back bad memories.
– sentimentTrack_Bitter_LT_grudge
– Festering Grudge
– sentimentTrack_Bitter_ST_breakup
– Bitter about Breakup
– sentimentTrack_Bitter_ST_divorce
– Resentful about Divorce
– sentimentTrack_Bitter_ST_fight
– Grudging after a Fight
– sentimentTrack_Close_LT_generic
– Deeply Connected
– sentimentTrack_Close_ST_adoption
– Open-Hearted
– sentimentTrack_Close_ST_generic
– Closer from Happy Memories
– sentimentTrack_Close_ST_nearDeath
– Close after a Close Call
– sentimentTrack_Close_ST_party
– Closer after a Fun Party
– sentimentTrack_Close_ST_qualityTime
– Growing Closer from Quality Time
– sentimentTrack_Enamored_LT_generic
– Deeply in Love
– sentimentTrack_Enamored_ST_generic
– Smitten
– sentimentTrack_Furious_ST_cheating
– Furious about Cheating
– sentimentTrack_Furious_ST_generic
– Furious
– sentimentTrack_Furious_ST_wedding
– Infuriated about Cancelled Wedding
– sentimentTrack_Guilty_ST_awkwardDate
– Awkward after a Bad Date
– sentimentTrack_Guilty_ST_badParty
– Ashamed of a Terrible Party
– sentimentTrack_Guilty_ST_generic
– Guilty
– sentimentTrack_Hurt_LT_generic
– Deeply Wounded
– sentimentTrack_Hurt_ST_generic
– Hurt
– sentimentTrack_Hurt_ST_rejection
– Dejected about Rejection
– sentimentTrack_Hurt_ST_romantic
– Heartbroken
– sentimentTrack_Hurt_ST_saddened
– Saddened
So for example... modifyrelationship Daniel Faraday Constant Faraday 100 sentimentTrack_Adoring_LT_lifesaver
Unfortunately, I am going for achievements, so cannot use cheats. Hoping EA might actually solve this. Guess we shall see.
