Good you're not doing that stretch. It's a pretty stupid stretch in general but especially for bad shoulders.
Remember, just because you don't pop it out doesn't mean certain things you might do are a know know. Certain swimming srokes are recommended against, for instance. You could talk to a PT about that. BTW, swimming tends to keep bodyfat on you
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One problem with these very unstable shoulders is the absence of pain. You may tend to get no feedback on the things you are doing. You are focusing on the things that are making it happen rather than on those things that may be keeping your shoulders from stabilizing as well as they can, which may be limited, I know.
The truth is that when they are loose enough you can get these dislocations without much injury in the right circumstances. But of course if that circumstance involved supporting a great deal of weight, the results could be very bad. I would encourage you to investigate what strokes to avoid in swimming, or maybe to drop swimming for something else.