Hi there. I also find exercise to be a trigger. But on the flip side, I have difficulty sleeping, and when I don't sleep well, I get a migraine every time. When I exercise, I sleep a lot better.
So I compromise by exercising lightly... enough that my body gets tired, but not enough that I'm so exerted I start getting really worn out or heart pounding (which is when the headache starts for me.) For me, this is walking briskly 30-40 minutes per day. On days I'm absolutely laid out and can't even zombie crawl from bed to the bathroom without hitting all the walls, I skip it because of the falling risk, but I do try to walk even when I have a lower grade migraine, again because it helps me sleep, and sleep is one of the things that eventually helps the migraine dissipate.