"It was clear that she was cheating on me. So I left her. But first I smacked her around. And then I told her exactly what I thought of her. I told her that all she was interested in was getting into the sack." […] He’d beaten her till she bled. […] What bothered him was that he "still had sexual feelings for her." (1.3.9-11)
Raymond hates his girlfriend because he feels his sexual attraction to her makes him powerless.
He [Raymond] asked if I thought she was cheating on him, and it seemed to me she was; if I thought she should be punished and what I would do in his place, and I said you can't ever be sure, but I understood his wanting to punish her. (1.3.11)
While Meursault doesn’t feel normal sex-related emotions himself (like love, or jealousy, or possession), he rationally understands when others feel them.
Part 1, Chapter 4
First we heard a woman’s shrill voice and then Raymond saying, "You used me, you used me. I’ll teach you to use me." There were some thuds and the woman screamed, but in such a terrifying way that the landing immediately filled with people. […] The woman was shrieking and Raymond was hitting her. (1.4.4)
Paradoxically, Raymond is at once so attached and detached to this woman that he abuses her for cheating on him.
Marie came over as we’d planned. I wanted her so bad when I saw her in that pretty red-and-white striped dress and leather sandals. You could make out the shape of her firm breasts, and her tan made her face look like a flower. […]
[…] I kissed her. We didn’t say anything more from that point on. I held her to me and we hurried to catch a bus, get back, go to my place, and throw ourselves onto my bed. […]
[…] She was wearing a pair of my pajamas with the sleeves rolled up. When she laughed I wanted her again. A minute later she asked me if I loved her. I told her it didn't mean anything but that I didn't think so. She looked sad. But as we were fixing lunch, and for no apparent reason, she laughed in such a way that I kissed her. (1.4.1-3)
Meursault’s attitude toward and interest in Marie is basically sexual.
Part 1, Chapter 5
That evening Marie came by to see me and asked me if I wanted to marry her. I said it didn’t make any difference to me and that we could if she wanted to. Then she wanted to know if I loved her. I answered the same way I had the last time, that it didn’t mean anything but that I probably didn’t love her. "So why marry me, then?" she said. I explained to her that it didn’t really matter and that if she wanted to, we could get married. […] Then she pointed out that marriage was a serious thing. I said, "No." (1.5.4)
With characteristic emotional indifference and detachment, Meursault answers Marie’s question with brutal honesty. However, his honesty betrays his ignorance of the range of human emotion, and perhaps even more than that, his primarily sexual interest in Marie.
Part 1, Chapter 6
Just then his wife was laughing with Marie. For the first time maybe, I really thought I was going to get married. (1.6.6)
Meursault’s emotional landscape begins to mature and grow more sophisticated.
We swam a few strokes and she reached out and held on to me. I felt her legs wrapped around mine and I wanted her. (1.6.9)
Meursault never says anything about Marie as a person. She could really be any nameless woman, since all he likes about her is that she is, in fact, a warm person to have sex with.
Together again, Marie and I swam out a ways, and we felt a closeness as we moved in unison and were happy. (1.6.7)
Meursault’s "happy feelings" toward Marie are really only based on physical feelings (like the "closeness" of their bodies).
Part 2, Chapter 2
She shouted again, "You’ll get out and we’ll get married!" I answered, "You think so?" but it was mainly just to say something. (2.2.7)
Whatever sense of closeness Meursault has developed for Marie was short lived; detachment is now all that is left.
Marie shouted to me that I had to have hope. I said, "Yes." I was looking at her as she said it and I wanted to squeeze her shoulders through her dress. I wanted to feel the thin material and I didn’t really know what else I had to hope for other than that. (2.2.7)
Even while he’s in prison, Meursault can only be comforted by the physical, not by words or emotional support.
I never thought specifically of Marie. But I thought so much about a woman, about women, about all the ones I had known, about all the circumstances in which I had enjoyed them, that my cell would be filled with their faces and crowded with my desires. (2.2.11)
Why would Meursault think about Marie? To him, she is just a generic woman.