Hi, and welcome! Well, it's good that you are thinking you CAN manage on your own if it comes to that. You don't have to make any immediate decisions, but you have a lot to learn about alcoholism.
First, it's virtually impossible to diagnose depression in someone who's drinking the way he is. Alcohol is a depressant, so many, many alcoholics are "depressed," and it improves dramatically or disappears entirely with continued recovery and sobriety.
It's also pretty useless to engage in marriage counseling as long as an alcoholic continues to drink. The alcoholism affects every aspect of the alcoholic's personality, and they are (as you've seen) very defensive about it and protective of it. They will blame their drinking on everything but themselves--it will be your fault, the stress of the job, yada yada.
I think the first steps for you are to find an Al-Anon meeting and start attending. Al-Anon is completely separate from AA, which is for alcoholics. Al-Anon is for friends and family of alcoholics or anyone who is affected by someone else's drinking.
Educate yourself about alcoholism. There is a lot of great information in the "sticky" threads at the top of this forum. A couple of good books that will get you off to a good start are "Under the Influence" and AA's "Big Book"--here's an online version if you want to take a look:
Big Book online. You might also want to try attending a few "open" AA meetings on your own. It can be a very eye-opening experience.
I've been in two marriages to alcoholics, and I'm eight years sober, myself. I've been around AA and recovery since my first husband got sober 37 years ago. Recovery is possible and real (first husband still sober), but nobody does it until they are ready. It sounds as if, right now, your husband sees nothing wrong with his drinking--YOU are the one who has a problem with it. It could be years or decades before he decides he's ready to be done with it, or he might never get there.
Right now it sounds like things aren't too horrible at home, so there's no emergency, but alcoholism is progressive, so it won't stay that way forever. As far as "cutting back," IF he is an alcoholic, that will not be possible. Not over the long term. And most alcoholics eventually start lying and hiding their drinking once it becomes a contentious issue, so you can't assume he is actually drinking less based only on what you see.
Glad you're here--stick around, this is a great place for support.