I have a slightly different story, I haven't had children but have had 2 episiotomies due to vaginal surgery for localized provoked vestibulitis (basically painful sex and pain when sitting or pressure on a certain part) I had it on July 3rd this year and still haven't been able to have sex because it feels like instead of making me bigger (in their words...giving me more capacity.....cringe!!!!) It feels like during healing its tightened up. I will absolutely refuse episiotomy during labour without doubt and will do everything in my power to not tear, if that means a longer labour so be it, baby will come when he or she is good and ready.
I also had vestibulitis, though it doesn't sound like it was ever as severe as yours (I only had pain with sex, not in other areas of life). Don't give up hope! My symptoms these days are vastly reduced, and sometimes non-existant. I think giving birth helped a lot, though it took a while for my hormones to return to normal (still had pain until I got my period again).
I did have significant discomfort the first few times I had sex after giving birth, but it was a different type of pain. I could feel the scar tissue from my episiotomy stretching. These days, though, sex is way better than it was before I had my LO.
Have you worked with dilators at all since having your surgery? I'm wondering if that might help with the scar tissue.