I swear by using the dilator. That said, if things have gotten especially tight, I see a physical therapist that specializes in pelvic floor disorders. That is, by far, the biggest relief I've had.
My stool has been really runny for years and I've tried to thicken it up unsuccessfully in the past with prescriptions from the GI, OTC things to add bulk, etc. I read a tip from another member on this site that helped me a ton - use regular Metamucil with a little bit of water (instead of a full glass that the package recommends). I started with sugar free, which helped, but the regular formula (again, recommended by the same person) is easier to drink. Made a huge difference to my stool/frequency, but also made a difference to my sphincter - I think having to push out something of substance keeps things more flexible, which correlates to a sphincter that isn't on lock-down.