- your husband’s mental health is NOT your responsibility
Although not complete -the other party has freedom- you hold partial responsibility for your spouse. And with mature charity comes the will and desire to be responsible for the other. [This is Karol Wojtyla in “Love and Responsibility”.]
Now, given mental illness: only a very knowledgeable person would have psychological knowledge on how to handle it correctly - which is always challenging. But that is not therapy, only dealing with the person of your family you love. Therapy should always be conducted by a professional not a family member. It does help if the one knows some psychology and how to correctly deal with mental illness or personality disturbance.
you should go to therepy to ensure you are not being verbally/mentally abused.
To know exactly what abuse consists off is a good starting point [
you recommended a book about it a couple of months ago that I found somewhat inadequate and exagerated - being on the NYTimes means trendiness more than quality ]. Because, you’ll hardly find only one party being abusive. It tends to be a mutual cycle of aggression action/reaction. And the clear identification of the (let’s not call it abuse but

aggression mechanisms/techniques and their psychological effects serves also to break the link in the chain of violence on our side -not letting ourselves be affected- to start with both in causing and effects.
This needs to stop. There is no use drinking. Substance dependence is a terrible thing to interrupt. It heavily affects the person, to some extant your husband is not himself.
the priest was distant with me.
Some priest don’t have a real knack for confession. It is not your fault. A priest in the image of Jesus does not reject the repented sinner, nor make judgement, nor hold untold preconceptions. You may be right, or the priest might himself be going through a tough time. Don’t think to much of it - he is only a priest who might not know how to deal with such a situation.
My husband is on many different medications, but still has anxiety/depression/alcohol issues.
I am sorry to hear your husband is sick. Don’t give in to wrath. It is not only a work of mercy, it is a beatitude!, to care for those who are infirm.
he says it is partly my fault
Here is a catch. We are each responsible for our own actions. And our actions do have effects on others - and might tip them over the edge. A person may very well not be able to deal with infidelity. But at one point all need to assume their own responsibility, to forgive, to heal, to love.