I've posted about my ex being in my home. She triggers me so frequently, but more the thoughts of her than actually her. Though I don't trust her in the least, i do see the positive changes she's made since being freed of her awful friends which I contend were a big part of the problem. I got really physically ill last time she was in my home.
But peep this, I drove over an hour and a half with her in the car, and only her and I. I didn't freak out, partly because I had control. I was the driver, in control of the vehicle, in control of something. That was the tiniest bit of soothing to me. I was also wired on caffeine and am currently a bit manic (I have PTSD plus ADHD plus bipolar type one and experienced SA as a young child and she was abusive in almost every possible way). She jabbered the whole way, mostly about herself, and I said a lot of "uh-huh" and "ok" and "oh." Eventually I started to loosen up a little. We had a little of ok conversation. Ok conversation is something I wanted with her for so long but got none.
Find something you're in control of, and use it to center you. I do things to the extreme because I want to be better, because I'm tired of avoiding what hurts me. It's rarely done that "full on" of a way, but that bit of control I had made such a huge difference.