Diet (especially getting enough omega 3s and fruits and vegetables) -- as well as other lifestyle issues and stresses -- can have a big effect on mood. So moving to a new situation may have helped -- like perhaps you spouse is a good at cooking healthy food? See for example my comments here on many factors of psychological health: https://news.ycombinator.com/item?id=15455259

And see also: https://en.wikipedia.org/wiki/Dialectical_behavior_therapy "This approach works towards helping people increase their emotional and cognitive regulation by learning about the triggers that lead to reactive states and helping to assess which coping skills to apply in the sequence of events, thoughts, feelings, and behaviors to help avoid undesired reactions."

Of course, all easier said than done...