It's much easier said than done as I've only been dealing with this for a few weeks compared to your many months - but I've made drastic diet changes:
- no meat
- fruits, veggies and whole grains only - count my fiber
- plenty of water
It's much easier for me as I have a home office but it's been working for me - no hard BM's for weeks and I take 200-300mg of Colase (ie DS)

You've got to stick with what works! I am pretty "anal" about eating too! :D