Without a lot more information it would be impossible to make that determination plus it is not our place to do so. You are right to not accept the status quo and seek help. With regard to your specific question, here is a link to a story about the different types of midlife crises that might help you. Based on what you have written you may want to consider counseling, either for both of you or if he won't go you may want to go by yourself. Good luck and let us know what happens.

Wesley Hein
Wesley [at] lifetwo [dot] com