This question made me nostalgic. I remember, I was 4 years old when my parents sent me to school. Some things I remember myself, and some were told to me by my parents. I didn't like going to school as well in the beginning. So what my mother used to do was, she accompanied me to the school. She used to tell me that, she will be sitting just outside the class and she used to. I used to look outside, and she was there. So I felt good that my mother is out there. When she thought that now I am busy in what's happening in the class, she used to quietly escape from there. When I used to reach home and ask her, where she went, she used to say this to me very politely "I was sitting outside but your teacher scolded me and I came back home" and I was convinced. This cycle repeated for a week or so and then I started enjoying in school so I myself asked her to not come now. Sweet memories!
So you can do the same thing with your child as well. As you and your wife both go to work, you can take turns and accompany him to school every alternate day. He will gradually start liking the school and won't cry.
Don't sweat the small stuff and it's all small stuff.