I'm not sure if I read here or another site. The story I'm thinking of has a father giving his wife to their son to be his wife. I think the father is a workaholic and can't/won't spend enough time with his wife but still loves her and wants her to be happy. I think it starts when the son graduates college and starts a new job. His mother comes to spend some time with him and they end up falling in love (probably not during the first trip). The father suggests the mother spend some more time with the son since he's busy at work. That keeps up until the father eventually tells both son and mother that he's going overseas for business for good and he's arranged documentation for mother and son to be married (I think in vegas with a stay at a casino/hotel for a short honeymoon) and proceed as husband and wife. Somewhere in there the son and mother meet the son's boss and his wife while acting as a couple. I'm pretty sure there is a scene where the son has a layover in the city where his parents live and the mother meets him at the airport in a limo or something and they end up having sex in the car before returning to the airport for him to catch his next flight.
Any help would be appreciated. If it's not on this site but you know where, could you please PM me with the info?