Someone explaining their tinnitus symptoms made me realise that I had tinnitus for years. Until then I didn’t “hear” it because I just assumed it was normal.

Since then, I’ve realised that tinnitus is contagious! So I prefer not to talk about it just in case I pass it on.

For some reason this experience you are describing reminds me of a passage in "One hundred years of solitude" where a character is said to fall in love with a woman that only exists when she is needed.