I am so sorry Emile, you are living in a suspended animation nightmare.
This should not be happening...it really should not unless there is some underlying pathology that is preventing you from healing or making your tissue so fragile that nothing is holding and the sutures are pulling out.
Please Google Ehler's Danlos syndrome.
I have it and had pretty much the same series of complications post-op as you do...every surgery fell apart. Valves did not hold, my pouch fell off of the wall or twisted, I herniated around the stoma repeatedly and my valve would pop out, I got twists, blockages, occlusions and any other number of complications.
We discovered the Ehlers-Danlos when I way well into my 40's and had already had nearly 40 surgeries. Nothing held together like I did not have enough glue.
My arteries and veins popped. My skin could not stand glue, tape or flanges...outside bags were out of the question. Dr Cohen didn't understand why everything kept falling apart.
Then I got the diagnosis (double-jointed joints, fragile skin, ligaments, intestinal tissue...) and he was able to use a different protocol to sew me up and staple me...it worked.
We use permanent instead of re-absorbable sutures. Doubles lines, deeper bites (they stitch deeper into the tissue so that the sutures do not pull out), use sutures, stapels and steri-strips on my outside closure and keep them in up to 3 months (staples out after 4 weeks, sutures 6-8 weeks and steri-strips at 12 weeks, they sometimes put in a drain just in case)...lots of precautions but they work, I get better results and they are effective.
They also double-attach the pouch to the abdominal wall using an intermediary. First they had used a Martex ring that they sutured to the abdominal wall then sutured the pouch to it...now they use mesh.
I do not know if this will help at all but I am hoping that maybe something might.
Good luck girl and may this surgery be successful.