Am I wrong for being upset/ angry with my ex?

My ex husband and I share a now 3 year old son. On the Monday before Thanksgiving I asked my ex when he'd be by to pick up our son. He told me he'd get back to me on the time later. Thanksgiving morning he told me a laundry list of reasons why it wouldn't work out. Basically that it was an inconvenience for him to get him. My son can stay with me everyday all day and it wouldn't bother me any, but I felt so bad for our son that he didn't show or even call him. Today, Christmas eve, is my sons 3rd birthday. His father didn't call, nothing. Tonight I texted him to ask what time he'd be by to pick up his son tomorrow. He responded he wouldn't be because he'd be with his new girlfriend's family. I feel so bad for our son that his dad is ditching him on all these holidays and his birthday. My ex husband and I share custody we have every other week with him so it's no like he's a dead beat all year round. Am I wrong for being upset?