I don't have one, but my husband did due to a bad car accident damaging most of his intestines.
He didn't swim, and often the tape would fall off if he was in the bathtub for too long. (part of why it feel off more easily on him was because his skin was really sensitive to the glue on the tape, he'd get red bumps which probably contributed to it coming loose)
There's special coverings that you can buy at medical supply shops to protect the tape/glue from coming off while it's wet. Also, you can swim with a suit on that's somewhat water resistant, like surfer's wear. You should also wear tighter swim trunks with a higher waist to keep the bottom of the bag from moving all around.
I wish you well on your recovery Lordkat.