Hi, I'd like to help you with your question.
It sounds like your husband may have been through something as a child that caused his depression. He is not coping with it, hence his desire to put the cause of his depression on you. By not taking responsibility for it, he does not have to face it head on and cope with it. It may be that he feels facing it would be too overwhelming or it could be that he is also angry underneath the depression (the two are often related) and feels better blaming you.
It does not make sense that you could be the cause of your husband's depression if it started when he was a child. If that were so, he would have been fine before he met you and he would recover as soon as he left you and the children. But since he has not recovered and is feeling even worse, then you could not be the cause.
When your husband went to the psychologist, he may have told him all about how he feels you are the cause of his depression. However, the psychologist should have picked up on the blaming and realized that this could not be the case for the reasons I stated above. Also, any therapist knows that when they see a patient in a relationship, they are hearing only one side of the story. They should not make assumptions based on hearing one person's version. Plus, your husband was seen for only one session. That is not long enough to understand the situation totally. So either the psychologist is not very good, or they did not say that and your husband wants you to believe that was what was said.
To deal with this situation, it would help you to see a therapist yourself. The stress of coping with your husband's illness and his treatment of you can cause you to second guess yourself and also develop stress related problems. The support alone would be very helpful in your attempt to help your husband. Also, the therapist can help you learn ways to respond to your husband and advise you how to deal with his need for help.
Also, do any of the professionals in your husband's treatment team know of your fear that your husband will hurt himself? It would be good to advise them of what your husband has told you. If you need to, write down what he says to you. Then you can contact the doctor or psychologist and let them know of your concerns. Also, ask them what your options are if he should say he wants to hurt himself. There is a mental health law in the US that says if someone threatens to hurt themselves or someone else, you can involuntarily commit them to the hospital for treatment. Canada may have a similar law. Ask your husband's doctor or contact your local ER or mental health facility to find out. This will help you have a tool on hand in case you feel your husband needs help right away.
Educating yourself on how to cope and respond to someone who has depression can help you as well. The more you know, the less you feel overwhelmed by the problem. Here are some resources to help you:
When Someone You Love Has a Mental Illness by Rebecca Woolis
Helping Someone with Mental Illness: A Compassionate Guide for Family, Friends, and Caregivers by Rosalynn Carter and Susan Golant M.A.
The Burden of Sympathy: How Families Cope With Mental Illness by XXXXX XXXXX Karp
Talking to Depression: Simple Ways To Connect When Someone In Your Life Is Depressed by Claudia J. Strauss and Martha Manning
You can find these books on Amazon.com or your local library may have them for you.
I hope this has helped you,