He made a commitment, to save the world, so he was bound to accept Loki as she is, good and bad. But what he's learned of her, he not only likes, but loves. She's been an unexpected blessing in his life. Which is probably one of the reasons the rest of the Avengers have begun to embrace her. She's been good for Steve. Babies will be just as good.

"Aaa!" He protests at the pinch, but he's laughing now, too, giddy with affection and impending joy. "I'm outnumbered! This isn't fair."