Is Mersault a jerk or not?

From reading up to chapter 6, I have come to the conclusion that Mersault is actually not a big jerk. He has emotions but he expresses them "unusually". I believe that he is capable of compassion and love but he has this "nothing matters" attitude, preventing him from enjoying the good things in life. If he were to write his own manifesto, I have no doubt that his would be the most depressing one to read. On page 41 he says, "looking back on it, I wasn't unhappy. When I was a student, I had lots of ambitions like that. But when I had to give up my studies, I learned very quickly that none of it really mattered". I'd like to point out that he never said he was happy. Just that he "wasn't unhappy". I don't think that he was ever really happy or if he even knows what happiness is. He definetly hasn't found true happiness, in my opinion. Even when Marie practically proposed to him, he had absolutely no opinion of it. He sounded like he just didn't want to talk about it anymore. Although it doesn't seem like he expresses emotion, I noticed that he had a mini-reaction towards his mothers death on page 39. He says, "I realized he was crying. For some reason, I thought of Maman. But I had to get up early the next morning. I wasn't hungry, and I went to bed without any dinner". I find it very hard to connect to him but I think that by him not eating, it means he was sad. Maybe I'm wrong but that's my interpretation of it. I honestly think that he is just scared; scared of loving and losing. All his actions are to prevent him from participating in life. He has this whole monotone outlook on life because he has experienced loss or failure of some sort and it has changed him. From that first quote, he said he has to give up his studies and maybe his loss of "freedom" impacted him more than it would anyone else. His boss was right when he said that he has no ambitions. If he thinks that there is no point to anything, though, why does he sleep with Marie? If nothing matters, would it really make a difference if she was in his life or not? I think he is just confused; kind of how I'm getting myself.