Awh man, I can't stand musicians that can just 'hear' the difference just out of jealousy. Even as a semi-professional musician (very semi, very semi indeed...), I've had to work crazy hard to even hear the difference between two different notes when other people just 'get it'. People insist that I'm musical just because I'm interested and do gig with a band (or did play, depending on my arm), but I find all of it crazy hard; timing, pitch, rhythm, all of it, and while I can play some decent bass, I'm really untechnical and take ages to learn new stuff or to build a bassline to an original song.
I used to take flute as a kid with sheet music, but I wished I'd taken almost any other instrument, where the body is in control of what note is being played, rather than relying on a combination of keys or frets to guide the note into the right place. I kinda feel like it's 'cheating' and it's really hampered my ability to correct. I'm wondering whether putting markers on my cello to mark the 7th and 9th of each string will slow me down in the long-run, even if it's torturous at the minute.