Seeing as your problem seems to be more muscular than with your diet, I would say that you should explore relaxation therapies and alternative medicines. I've been constipated for years simply because of stress and a paranoia/fear of going to the toilet. Only now, that I am visiting an acupuncturist, chiropractor and doing yoga, am I starting to see results. It's amazing; as soon as they make an "adjustment" or put needles in me, I feel my whole abdomen relax and begin to move.
Changing your diet won't work if you're still psychologically hung up on having a bowel movement. The mind is key. Good luck.