I think all guitarists deal with memorization of music in varying degrees. Taking a break from a song and revisiting it a few days/weeks later usually reveals some memory retention, then I make a go at it again, thus advancing my memory of the song further. Each time I consistantly revisit the piece I get further along. This take time, patience, and stickability.

How many times do you think the Don Felder and Joe Walsh practiced and worked at memorizing the solo in Hotlel California before it was solid and ready for live performance? Now think about how many more times they've played it live! Do artists get board playing their 'hits' that they've played hundreds (even thousands of times)? I think yes. I've heard it confirmed from a few celebrity musicians I've personally talked with. Heck, I too get board practicing and getting songs ready for performance. I empathize wih you.

Advice: stick with it and keep revisiting the songs you want to memorize. If one doesn't kepp at it they'll never memorize a piece of music.

-Dave