You need to decide if this is a dealbreaker for you. Sounds to me like he did it again because he thought probably be temporarily mad and then you’d get over it, and therefore thought he didn’t need to prioritize your feelings about it. It’s really inconsiderate, especially when you live with your partner and they’re expecting you home, to tell them, “oh yeah I’ll be home by x time” and then just not show up at that time and not call or text to let you know the plans have changed.
Like @cherryade said, he could have asked a friend to remind him to text you, he could’ve set an alarm on his phone for whatever time he told you he’d be home and then called you at that time to let you know if he was coming back or if plans changed. He chose not to.