Sorry about your DH's colostomy. I have a permanent colostomy also. As far as I recall, it took several months to come to terms with it. In my case, reading about others on the Colon Club help[ed a lot. Lots of folks here have it far worse than I do.
As I was getting used to 'Totoro', (my quite large stoma, who my surgeon refers to it as a work of art), small things would make a large difference to my situation. One day I realized I could tuck the bottom of the bag into itself. I was delighted, no more worrying about it hanging below my shirt. The day Coloplast released the Sensor Mia bag, I was almost giddy with delight. No more issues witht the bag ballooning with gas.
At this point, is your DH's main issue with noise emanating from the stoma? If so, there are products that help. Try googling colostomy muffler
Here's one called the Stoma Stifler...http://www.stomastifler.com/stoma-noise-suppression.php
. Created by a mechanical engineer...
The Advantages of the Stoma Stifler for Colostomy and Ileostomy Sound Control
"Avoid embarrassing moments from stoma sounds.Special geometry: The tapered edge along the perimeter provides gentle flex, and contours to individual body shapes. Around the cup and along its spine, the Stoma Stifler has a thicker cross-section to withstand impact and suppress stoma noise.The Stoma Stifler weighs less than a Smartphone, and you do not have to wear it all the time if you choose not to due to the magnetic clasp, which allows the user to put it on and take it off within seconds, easily, without undressing."
Another, https://www.stomabags.com/stealth-belt- ... 1-per-each
. Stealth Belt - Muffler-Neoprene Insert To Muffle Stoma Noise. One of our former members, KT, used to wear a stealth belt, and was an active rock climber. I recall he often recommended the product.
Hopefully, there are products available to help with the noise problem. I think trial and error can be of assistance. Also, as others have recommended the people over at the united stony site are rally helpful.