Has he made up his mind?

So my partner and I have always wanted more children. I am a step mommy to a beautiful 5 year old girl already.

We always talked about, made up future names, what we would change about our lifestyle when pregnant. Everything.

A few weeks ago, I had a breakdown and panic attack. We had a huge fight. And now he is saying he never wants to have children. He has said this before, but just to hurt my feelings in a fight. But now the fight is over, and he is still saying it. He says all of his attention and time should go to my step daughter and he doesn’t want to take away attention from her. I am 22, we were planning on having our first together in a few years. How can someone change their mind so quickly and be dead set? Who knows how he will fill in 3 years right? A person grows and changes. Ignore him when he says he never wants children again? Or accept it and keep in mind that his mind can change?