I hope you and the DC's are ok and safe OP. This may be a one off, he may not do it again but you still need to get the incident logged. I never thought my xp would kill me but I also never thought he would hurt me in any way either. Sadly, you just never know what anyone is capable of. So just incase you do think this is a one off and will never happen again (as I did) this is my story;
My Xp was sometimes moody/grumpy he occasionally punched doors etc in anger but never lifted a finger to me. We split up because of it, he would cry and beg and swear never to do it again, I took him back but it continued. It wasn't frequent but it still wasn't nice.
One time we split and I went out for the evening with a girlfriend of mine, it got late so I decided to stay over at hers for the night. Unbeknown to me xp had broke in my home, switched the electric off at the mains and waited for me to return home. Who knows what he had planned?
I still took him back after that after his pleas. He was good at getting under my skin and making me believe him. One night we were out together and he accused me of flirting with my bf's fella and pinned me against a wall by my throat. I ran in fear when a passer by pulled him off me. In all the confusion he managed to get home before me and hid I had no idea he was home when I arrived and I locked/bolted all the doors so he couldn't get in. I kept all the lights off incase he arrived back home so he wouldn't know I was there. I went to the bathroom and when I came out he was stood there with a knife, he put it against my throat and threatend to kill me & then himself. I somehow managed to get back in the bathroom, lock the door and stayed there for hours till I knew he was a sleep. I fled as soon as I could and got to a neighbours house.
That was the final straw and I never saw him again, I got an injunction against him and all the locks changed. I don't know what he was capable of in the end but that was what he called loving me. I never imagined in a million years he could do any of that, you just don't know.
Please please take heed and think of yours and your DC's safety 