Exposure to OW's family causes embarrassment to her that can be a deterrent unless her family is wacked...which is a possibility. Are they co-workers? Then go to their boss.
I would say OW's husband only.
In my case, I exposed to OM's parents, because he still (at age 29!) lived with them, and he was studying to become (and getting very close to becoming) a COP, and I thought they could exert some influence on the wisdom of his choices on his potential new career. It didn't seem to help any. But if he had been married, I'd damned sure have exposed to his wife.
