Dreamy Romantics are not Realistic
so I don't think that this person had feelings for me previously.
The person is feeling a rush of romantic feelings (Knight of Cups) that were brought to a sudden stop by the revelation..(The Tower)
What CrystalSeas said. You're talking facts and reality. But this is FEELINGS and FEELINGS can mean people running on imagination and faulty memory or just a picture of you on the internet and what it says on your Facebook page ("Wow! We both into surfing! This woman of my dreams!"), If a man or woman can FEEL that they are in love after a minute of reading a stranger's Facebook page and looking at a picture, then I think a guy who hasn't seen you in 5 years and just reconnected can FEEL it too. Especially a romantic dreamer like the Knight/Cups.
Of course, being the Knight/Cups also means his feelings aren't real reliable. Knight/Cups is the sort of guy who falls in love every other week. And he might mean it sincerely each time, but if you want a reliable lover, go for the King/Cups, not Knight/Cups. Getting back to this reading: He could have recalled something about you that happened 5 years ago, and made up his mind that he's had feelings for you all this time--whether that's true or not is immaterial. Then he contacts you, interacts with the REAL you, not his imaginary you...and now those feelings have been brought to a screeching halt.
OR...he might be a dreamy romantic, who had no feelings for you, is, in fact, hopelessly in love with someone else. He contacts you, you say something which to you is nothing, but to him it's profound. Bolt of lightening! Tower comes crashing down, "I'm in love with the wrong person!"
I don't know which of these scenarios these two cards indicate. You asked what they mean. They mean:
He feels he's had a sudden realization about his romantic feelings for you. That's all. It's up to you and the rest of your spread, to decide if that means he's realized he ought to turn his romantic feelings your way, or that his dreamy dreams of having a romance with you are not going to happen.