Her staying silent isn't the most encouraging, but he has to take her word for it. Later, he might admit that in part, it's because he doesn't want to stop. But right now, he's going with trusting her to tell the truth.

He keeps his eyes on her face as he pushes in and pulls back, pushes further, using the natural lube of two orgasms to hopefully ease it for both of them. Maybe it would work better if he went faster, but he can't risk it, so it's slow and...excruciating, in a great kind of way. She is so tight and it's not comfortable, but all the hints are there that if they can get past this, then it'll be amazing. His breath is already coming hard with the effort of restraint, her skin feels sticky against his in the heat of the room, and she is slowly, gloriously, crushing him to death.