AITA for refusing to give my husband a “paternity courtesy name” after our child was born from a sperm donor?

My husband (34M) and I (33F) used a sperm donor after years of infertility. We agreed on a name together. But now that our son is here, he says it would “make him feel like a real dad” if the baby had his name as a middle name.

I said no, we already agreed. He says it’s a small thing to make him feel included. I feel like he’s trying to erase the agreement we made together.

AITA?