It is these people who continue to leave others with the impression that tarot is 'nonsense'.
I am a 'betting man' and I would wager that just about every person here has, at least once, listened to a song and found some enlightenment, guidance, inspiration, validation....
Readers will say to the client, 'this is just one of many possible futures.' The future (or 'outcome' as we call it, I personally call it 'potential direction') is what is -most likely- to happen if the client keeps doing what they are doing. In your story maybe the reader was right, and the clients belief in it perpetuated the end of the relationship sooner, which is actually better in the long run.
The reading proved to be a benefit, saving the client from many days of emotional drama.
But if you want to research, I can provide lots of material.
I havent done any research per se, but have dedicated alot of thought to this subject because quite a few women I have dated, seemed somehwat involved and believed in horoscopes, tarot cards.
It has ompacted me for life, but i steepped away just in time. And the bit about self-fulfilling the future is quite valid. Yes, the mind is powerful in that way, weak or strong.
You expand on the example i provided, of someone ending a relationship sooner due to subconscious action based on a reading, and you say perhaps its good because they are saving time this way.
Now let me confuse you a little bit..the right hands, tarot can predict the future, but its not really the cards, it's the reader.
Some parts of our futures are things we have NO control over. 12 cards where used for the reading with the final 3 being 'the future'.
If the client did not want the relationship to end, then they would take the extra steps needed to avoid that.
Readers all over will often use the same 'punch line' - "your future is not set in stone" The advice and information presented by the cards is often things people already know, but are ignoring it.
In it's genuine form, this is exactly what Tarot does.