How can I get through to my husband?

So my spouse and I have been married only 3 years now. We have 2 kids, and another on the way. When we met he was in the service and was about to end his contract to readjust to civilian life. Since he got out he has tried several different jobs and has even gone to college. Things for us are mostly fine but I’m starting to notice a pattern in my spouse. Every time he starts something new, he finds a way to find all the negative things and immediately gets frustrated and quits. He has worked job after job but does not like to do any of them. I have been patient and encouraging but it has also been so draining on me emotionally to see my spouse suffer constantly. When I suggest I get a full time job and he stay home, he refuses. I do contribute financially as I go to school and am self employed but it’s the emotional problems that are weighing on our marriage. How can I be more supportive? I listen when he vents about work, I offer encouragement to try and remember what’s important about having employment and how hard it can be between jobs especially with bills not pausing. I am more than willing to work. I have been paying for bills when he’s in between jobs. I have even suggested going to a counselor for possible depression from adjustment to civilian life from military life. Each time I try to get through to him in a kind way, he takes it as I don’t understand and he’s all alone. I’m afraid of him pushing me away because all we have is each other, we don’t live near family or friends. I love my husband and want to continue to be there but how else can I get through to him? All of our needs are met at home, and with the kids but when it comes to his issues at work he thinks I don’t get it and shuts me out now. How can I approach this?