This is your boundary. You have presented it in the most direct way you could without venom or hate mixed in. Bravo to you!!
His responses are expected. Try to let them go. It is far more important that you put those words out there than whether it sinks in for him.
Once I made the decision that the time had come to leave my XABF whom I had lived with for 10 years and who I was relying upon financially for the last 3 of those, one of the toughest things for me what to resist the urge to give it yet another try. It was just so hard and so terrifying to strike out on my own. I had a house to pack up and move with many pets including horses and I had little money and few resources.
It helped to post to SR when I struggled and the wise folks here reminded time and time again why I was leaving and why it was so important to stay strong.
It helped to write down my feelings when I was empowered so I could refer to them when I was low and ready to give up.
It also helped to pray for strength and serenity every morning and throughout the day.
The toughest time in a strained relationship is during the separation whether it's temporary or not. Mixed feelings can bring mixed signals, which can bring confusion to the one being asked to leave and guilt and stress on the one doing the asking.
Keep safe. Stay strong. Look to your children when you need the strength to hold your convictions.
We're here listening if you need support.
So proud of you for protecting yourself and your children. Doesn't have to be permanent, like you've said, but you're right that it must be done for the health of all of you.
Best wishes!!
Alice