Fiances tempertantrum

What kind of a grown ass man has a full on tempertantrum and forces an iceblock down your shirt, threatens to smash the glass door you are standing beside and also threatens to break up with you over a simple miscommunication? Like seriously? My fiance got a text from his ex today asking if she could drop my step daughter off with us early today (its our normal pick up day for our week with her) as she has a doctors appointment. He texted me first and asked if I would be home, I told him I couldn't guarantee I would be home as I was planning a hike with our dog so I asked if she could drop her off with him at his work and I would come pick her up from there (he was just going to have her stay at his work until he was off but I told him it was fine, I would come get her from there). Well, I finished my hike just before 4 which was when his ex wanted to drop my step daughter off so I thought it was perfect. I drove to my fiances work to pick her up. His coworker said he has already left. I was super confused so I drove home to find him at home . He immediately flipped out at me saying if I was going to be home at 4 why did he lose an hour at work and he went on and on. I was really confused and told him "no, I told you I would see you at your work around 4 but I didn't know an exact time as I would be on a hike". I stood there while he chopped away at some ice in our drive way trying to calmly explain the miscommunication and he just flipped out basically telling me it was my responsibility to be here so his ex could drop off his daughter and so on and did what I mentioned above. He blamed me for him missing an hour of work and refused to listen to me and was literally acting like a child. Hes now literally locked himself in our bedroom while I am here entertaining his 4 year old. I just dont get it. I get that miscommunications are annoying and it sucks that he missed an hour of work over it but did it really warrant that kind of reaction when all I was trying to do is have an adult conversation with him?