Heather, Those little fits and starts of a crisis in your marriage may have been the life transitions that we all go through. Some go through them w/o a blip on the radar and others, those who have poor coping skills, act out. If people can't navigate those transitions well, a more difficult crisis will arise in their 40's, 50's, 60's, or even 70's. Again, it all depends upon individual, their childhoods and coping skills.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
