Questioning my boyfriends ability to provide...

Let me start from the beginning, I have two children from a previous marriage. When I met my boyfriend I was living on my own working full time and caring for two kids mostly on my own. He was living the bachelor life renting a house with a group of friends. We both had jobs. Not great jobs but providable jobs. He moved in with me and my kids after dating for a while. He had to quit his job to make the move over an hour away with me. I knew that and was ok with it. I was the bread winner for the first 6 months or so of our relationship and also fine with it. Last October I lost my job and thankfully my boyfriend had gotten a pretty good job the same day. I of course panicked because I didn't want to rely on anyone every again. But after a month or so of my boyfriend begging me to stay home because my youngest is autistic and needed more of my attention I reluctantly agreed. Everything was actually going well. Then about 3 months in to his new job my boyfriend started getting kind of F at work. He quickly found another pretty good job. Then again everything was going smoothly again. Now hea been at this new job for about 3 maybe 4 months and he's getting in arguments with the other guys at work. He's calling out or just not going. I'm starting to get concerned that this might be a pattern. I'm a very scheduled person and I hate when things change. He's the opposit. Normally that doesn't bother me but in this case it really does. Iv told him that even thow I love being home with my baby's I'm more than willing to go back to work to help out. He just keeps telling me no he really wants me home. 
I want to talk to him more about how much this is bothering me but he gets so upset when I bring it up and it ends up starting a big fight. 
My question is if he's switches two jobs for basically the same reason in lest than a year should I be concerned or am I just thinking to much about it???