One thing I've heard and read is that people will "affair down" continuing to go down-market on each subsequent one.
A good mood could also be an indication that she's getting her happiness elsewhere. I know that my W would be in a great mood with me after secretly spending time with OM.
Of course I could be completely wrong about all of this too.
On BD H52, W50 T27, M26 S21, D23 BD-9-Mar-16 D-15-Jan-18 Final-19-Apr-18 I am a storyteller. The story may do you no good. But a story is never for the listener. It is always for the one who tells