He enjoys her "protection", which is an intimate feeling, delicate and peaceful. Just like the mottled light and shadow they bathed in the shade of the trees on the day they met, or the coolness of the glass of iced Americano, or the fluff on the surface of the peach, or the strands of hair popping out of her buns under the sunlight, and the fragrance of the same shower gel they chose tacitly.
It's the kind of emotion that seeps out from the bottom of our hearts just by looking at each other.