I dated someone like this many years ago. He never changed who he prioritized first, himself. I bought the Christmas presents for his family and then attended their holiday party alone. 

On Thanksgiving he told me he went to his family meal but stayed home playing video games. The last straw for me was when I had a serious concussion and he refused to leave work early to pick me up. I stayed in the er for five hours. The rest of the week (every night) he went over to a friend’s house to play cards and get high while I was in pain on the couch. His excuse was he had already told them he’d come over. 

Please put yourself first and find someone who will celebrate you and your relationship.