I'm sorry for your loss. I can somewhat relate, while we were not trying nearly as long as you were, we had a blighted ovum on our first pregnancy. We went out and told everyone we were pregnant early, and found out the day before Christmas Eve that we lost the baby.
As far as the sex goes, were you cleared medically for sex? We had ours ended surgically (as my wife didn't rejected the empty amniotic sac, in fact, she was still experiencing all the symptoms of pregnancy only without the baby, which made it worse), so we weren't cleared immediately to try again. He might not think it is ok.
What I am assuming is the case right now is that he is grieving. While you have your daughter, who is blood, he does not, no matter how close he is to your daughter, have a child who he helped create. Either way, he is grieving and right now having sex, what he may see as part of why he feels the way he does now, probably is nothing that is even remotely interesting. Not because he doesn't love you, but because he can't even think of losing another at this current point in time because this one is so fresh.
You need to allow him to grieve, offer to let him talk to you about his feelings (he may reject that due to stereotypical gender roles), and if he takes you up on it, just listen and offer an open ear and shoulder to cry on. I know it is tough on you too, but if you allow an open dialogue it will help everyone. It took me some time to get over the loss and to be frank, I was hesitant when it was time to try again because of fear of a repeat situation, but fortunately our 2nd attempt is now almost 23 months old... so just because it happened once, does not mean a guaranteed repeat.