but I think it's only natural for them to bring up their wives on without guilt or bad associations.

Absolutely. The characters don't exist in a vacuum. They have histories. Prior relationships. Back story. Mind you they aren't going to be thinking constantly of Sara / Sha'uri / Becky Templeton from 10th grade/ etc. but there will be times that the situation calls up a natural association with a past experience. This is a good example of one such time. :)