I'm actually the one who is hesitant to move in together, believe it or not. I have two teenage kids, and it's one thing for me to willingly ride the PTSD rollercoaster. It's another to make them deal with it with no choice in the matter.
He's never snapped at the kids, or said anything mean or off to them. Honestly, I don't think he would, but if he does it to me when he is stressed, what's to say he wouldn't do it to them when he is stressed? And even if he didn't, like I said before, I don't want my kids, especially my daughter, seeing a man talk to their mother like that and think that this is an acceptable way to treat your spouse/partner.
My son is starting college, and my daughter only has a few more years of high school. I'm very hesitant to move in while she is still a minor.