What should i do? *Long*

Im at a loss at this moment my fiancee and i have been great right now, hardly fights at all. He got his cdl a few months back and the route he is working at the moment sucks. So not a lot of money we also have 3 kids. He talking about just quitting and im trying to defer him from that option because he has always been this way. Up until i had our last baby i was working as a cna long hrs hard job everything. Providing for all of us for years! Just my income while he sat around i start school for nursing on the 14th and he hit me with this. Im so mad and frustrsted about it because he cant wait til they fix the route or transfer to another. Im trying not to be rude about it but i am extremely livid about it not for the fact i would have to get a job but because it is the same old thing with him. I truly thought it would change but it has not clearly. I dont even know what to say to him without being mean. Maybe im being dramatic but it is a pattern. And it is rearing it's ugly face to me once again. I told myself once our last child was born if he does not do what he needs to i will leave him because i am so sick of this whole situation its been 7 years of this. I love him but im over this stuff i thought his cdl would change it all but it didnt clearly. Im devistated right now. I dont know how to handle it... if you were in my spot what would you do? Because im to the point i dont know anymore.