what else have you practiced or implemented when trying to deal with stressful situations.
For me, most of the work happens before an interaction. The big three, diet, exercise and sleep are the most important things; if I'm eating right, getting a decent amount of exercise and sleeping enough, but not too much, all of life goes better, and I've got the emotional resiliency to manage my emotional state in times of stress. Also, nutritional supplements like calcium, a natural calming mineral, and vitamins B, C, and E help my body find that place of calm. Plus staying hydrated is easy to miss and very important; most people are usually dehydrated, and drinking at least 2 liters a day of clean, pure water can really work to help us find balance. And then there's what I don't do: minimal coffee and other sources of caffeine and no alcohol.
All of those things make maintaining my emotional state much easier, and then if I do end up in a stressful situation, as will happen here on planet earth, it's about focus: what really matters right now? What's my goal? What's good about this situation? The right questions can help frame the interaction so we can stay chill.
Of course I've found interacting with someone with a mental illness, someone who lives in perpetual chaos and shuns rational thought and logic, is the advanced level. There were times when I wasn't managing my state well, and got caught up in the crazy, and other times I was managing it well and was able to detach a little while we were in the middle of the next drama, and look at it more objectively, and the whole thing was so ridiculous it was funny. It also became clear that it would always be like that with her, and the best course was to just leave her; sometimes managing our state includes removing negative influences.