Here is my experience (2 piece Convatec system).
Showering: I shower with my appliance on. If it's a longer shower, the adhesive does start to peel away from the body. And I can tell that the glue overall is mushy. This is especially true if the flange has been on for 4+ days (I get 6 days from the flange portion). If it's the first or second day for the flange ... not so much softening of the glue/peeling.
Swimming: I must be hot stuff
- because lake/pool swimming causes the same as above.
Hot tub/bath tub: flange portion loosens after about 10 minutes - so I do neither of these right now.
Looking into Sure Seal Rings. Have used tape, but for it to be effective, I have to cover the entire adhesive area.