Meursault wouldn't describe the buildup to this as some kind of 'tension' that needed to be resolved. He was a straightforward man, and had no shame in knowing what he wanted. It was a mere satisfaction of a desire; just as anyone else, he had needs, and wants.
In the moment, he simply had wanted you. Sleeping together had been more of a... mutual agreement.
Right now, in the aftermath, he had the familiar craving of a cigarette, despite having stopped smoking for some time now. Perhaps it was simply force of habit. He was still flushed from the activity, and judging by your own breaths, he wasn't alone.
The white ceiling was reminiscent of his room, and even, if he concentrated enough, he could smell the sea like in Algiers. He sighed, and sat up with the purpose of getting dressed. When you embraced him, his muscles tensed, ever so slightly, but he made no move to get away. The sensation was pleasant; a warm body, pressed to his own.
"It did not mean anything." He says, perhaps with an inkling of what you must be thinking. "This was merely to satisfy my desire, and your own." It was all indifferent to him. Things like feelings, connection, bonds... they mattered little in the absurdity of life.