Depressed husband

Hi ladies. I need your help. My husband has a extremely depressed to the point where I don’t understand how deep it is. We’re expecting baby #4 and he just isn’t happy. (The birth control failed us)

He says he’s so depressed with life and marriage and I don’t know what to do for him but try and be there along with listen. We’ve been on a “break”.

Do you guys have any advice on how I can help him. I’ve never dealt with this before.