Our neighbors told us they would swing... I think hoping we would. Told them not interested. Then they joked about how their 1st experience the couple was divorced, I said, no duh. They were not happy that I thought it was just the step right before divorce.
After their life blew up, rehab, divorce, 2 kids in serious therapy (1 survived, the one that is friends with my son)... It a fait accompli that leads to eventual demise of the relationship.