I would suggest you start practicing some form of meditation. If you do it early in the morning, it will probably go unnoticed by your wife who might think that you are getting involved in spiritism, afterall, yoga is spiritism isn't it? (Don't tell that to my physical therapist...he would really be upset considering he is an atheist!)
There are many forms of meditation. Concentrating on your breathing, a zen form, is one of the most calming. As you draw in a breath, try to clear your mind. (Contrary to the JW mentality this DOES NOT open the channel to the demons, they are busy doing other things like possessing smurfs!) When you find your mind wandering, pull it back and concentrate on the breath. Breath through your nose if you can. First breath should be deep and full. Next breath normal, then fall into a rhythm of breathing counting each inhalation and exhalation as a breath, 1, 2, 3, 4,...unitl 10. Then start again, all the while bringing your concentration to the breath, especially when your mind wanders.
After a few days of this, your mind will readily fall into the pattern of clearing with the concentrated breath. As it becomes more of a pattern, you will find that when you lay down to sleep, you will concentrate on your breathing and your mind will relax...it will start to wander...bring it back with your breath. In time, your mind will quiet and nature will take over.
Take it from a person who suffered horribly from insomnia. It is a rare thing for me now not to be able to fall asleep when I go to bed.
SOP