The Mitzva to have children is one boy and one girl. Anything after that is voluntary. If you cannot afford to take care of them it’s a serious question for a competent Rav.
And thanks to the OP for bringing this up, whenever I see someone collecting because he has 13 children to marry off I wonder if he had a right to have them in the first place.
Before anyone screams what a horrible person I am, let me say that I give plenty of Tzedaka to these guys and I was not referring to a case of catastrophic illness etc, just a guy who has more kids than he can support. I think its very greedy for a person to have many children and throw the responsibilty on others