compersion in theory, brutal in practice — how did you actually bridge the gap, no podcast answers please

Im a relatively educated LS person, Ive read the books, I follow the right accounts, I can articulate the concept of compersion at a dinner party if needed. I get it conceptually. I think non monogamy is beautiful in theory. I support it for my friends without flinching. then I am in the room and my husband is having a great time with someone and my body goes cold and stupid and small. and all the theory in my head does nothing. all the podcast clarity does nothing. its like Ive trained for a marathon by reading about running and then I get to mile one and my legs dont work. I dont need any more conceptual frameworks. Ive consumed them all. what I need is the unglamorous in-body stuff. how did the long timers actually move from "I understand compersion intellectually" to "my body relaxes in the room". what were the small unsexy steps. did somatic stuff help. did certain rituals before/after meets help. did couples therapy specifically help. did just doing more meets and letting the body adapt help, or did that make it worse for you. I am asking the question I wish someone had asked when I started bc the gap between theory and practice is the gap nobody talks honestly about.