Do you believe or know of him having a drug problem?
What is your specific question?
You've shared that he had left his job and the insurance issue got in the way of seeing a counselor for marital therapy. You may be able to contact the United Way toll free #211 and get a list of community mental health agencies in your area (they serve clients without commercial insurance)
It would be imperative that he tells you where he goes when he leaves the house and why. If he is doing it as a way of avoidance, that is not a healthy coping skill (it only hurts your relationship) You would want to let him know that you would like him and you to work on resolving the issue not running away from it. He may be feeling overwhelmed by fatherhood, had burned out from his ex job, is becoming undecided of what he wants out of life and marriage, a possible early mid life crisis etc.
Unless he opens up, you would only speculate about the causes for his behavior. If there is a history of mental illness in his family such as depressive disorders/bipolar, it may be something to consider as a cause.
The below is a workbook suggestion for the two of you to consider-
The Couple's Survival Workbook: What You Can Do to Reconnect with Your Partner and Make Your Marriage Work by David C. Olsen (Paperback)
Why Can't You Read My Mind? Overcoming the 9 Toxic Thought Patterns that Get in the Way of a Loving Relationship by Jeffrey Bernstein (Paperback)