My boyfriend does not want to have children, because?

If he's truly firm about this, and being with him is more important to you than anything else, then I'm sorry: you're just going to have to focus on how to accept his decision rather than changing his mind. That doesn't mean you can't talk to him about why the change of heart and why you feel otherwise, but it's not fair to any kids you might have for him to approach the venture with reluctance at best. (And frankly, given the toll your health issues have probably taken on your body, conception might not be safe or even possible, so it might be in your own best interest to think about what life without children might look like anyway.)