Seton stitch surgery for abscess and fistulae

Hi, I dont have Crohns, or ulcerative colitis, i seem to have developed my abscess and fistula out of the blue, 18 months ago. I have had 3 surgeries for insertion and tightening of the seton, and am due to have another one this month. A lot of the internet stuff suggests that the seton gets tightened every week over the course of a few weeks, yet mine take place every few months when the surgeon feels the seton has loosened. Has anyone else had a similar experience? it seems to take forever to heal - i just dont feel that i have made much progress over the past 18 months since the first op?....thanx