How's this for a really random bit of a plot...
A woman had been having an affair, the lover either left her or died. The husband then stuck by her as she mourned/got over the break up even though he knew she was pining for someone else.
It is really annoying me. I can remember feeling the pain that he must be going through, but I can't even remember if I read it or watched it!!!
Any ideas? (I know this is soooooo unlikely)