How to convince him to stop pulling out?

Trigger warning: discussion of miscarriage: So, my bf and I have been together for a while and have agreed we both want more kids. We experienced a miscarriage back in October and once I was healed, we discussed if we wanted to keep trying. We agreed that we do, however, he said he doesn't want to know when I'm ovulating. He just wants to enjoy every moment together. But lately he has started pulling out more. He only releases inside if I'm on top or beg him not to pull out. Is it possible he is still hurting from the miscarriage and just isn't telling me? I got myself a necklace for the baby we lost, and plan to get a tattoo for the baby, but I don't know if he needs something like that as well or just more time in general. I told him how I get more satisfaction when he releases inside, not just because I may get pregnant, but also somehow it adds to my euphoria in the aftermath. If that makes sense. But yesterday he came over and even after I was on top, he looked like he was in pain and asked me to get off and then he released. Has anyone been through this? How do I get him to stop pulling out and just enjoy the aftermath? Do I need to ask him if he is still hurting from the miscarriage? I know he isn't cheating or anything like that, but I've never been in this situation. Can anyone offer advice?