So frustrated

I'm getting so frustrated with my SO. He says he wants a baby, we've been TTC for 7 months now but he doesn't understand that having sex just one time during my fertile window won't get me pregnant. He doesn't understand TTC means having to have sex every other day. We try but he has ejaculation issues because of a medicine he's on and he won't stop taking it. Honestly idk what else to do. It's like he just can't get it through his head that TTC actually means TRYING. I talk to him about it and he barely says anything. Maybe he really is lying to me about wanting a baby. I could just cry.