You were not wrong to send that message.
You were perhaps ill-advised though to have allowed him anywhere near your DC until you knew him better, but you wanted to trust him, I do honestly get that.
A man effectively forcing himself into your life by telling you he loves you too early on is doing so for a reason. He's using smoke and mirrors to get to you, because the 'real' him isn't good enough for you to fall in love with if he were to manage the relationship normally.
He's insecure, has a massive inferiority complex, a deep mistrust/hatred of women, and would be abusive.
He flipped over your attempt to do something nice, because he can't handle people being nice. People who react like this are sickeningly damaged, and seriously self loathing.
That loathing is what he'd turn on you and your kids in time.
You trusted the wrong man, he conned you, he had to, because he's a terrible man.
Tell your kids that something's come up, and go and do something ELSE just you and them (different place too, or he might crash it)
Have your previous relationships been abusive too?
If so, you need the Freedom Programme pronto, no more dating until you've done it. Learn what the signs are, the acts of abusers, and hold yourself back a bit. It's an act of self love to make sure someone is ok, and actually to demand that they are good enough for you, and good enough for your DC.
Don't settle for scraps.