Why was this a shock to him?

My birthday was in November and it was on a school day. When I went to school I only told a few people that it was my birthday cause I knew it would get around fast. Bu at the beginning o the day my cousin Shilah and my friend Maya went up to my ex boyfriend Devon eskelson and told him that it was my birthday. I did not know about this plan. He was the first person to know. My cousin said that he didn't believe them. So at lunch he came up to me and ask if it really was my birthday. He knows I would never lie to him and I told him that it really was my birthday. He told me that he would get me something when he got money and then a week later he got me a card with a special note in it that said he missed me and he still loves me. We dont want to start dating again cause we know it will bring drama to the table. Why was it a shock to him and should we start dating again???