Why hasn’t he introduced me to his family after 4 years?

We’ve been together for four years now and I still havent met his parents. Not even once. We talk about marriage sometimes but it feels fake when his whole family could be on another planet for all I know. His mom calls him every Sunday and he never says a word about me. I overheard him once redirect the conversation real fast when she asked if he was seeing anyone. I get it families are complicated especially when you’re from a Vietnamese background like me. My parents worked their fingers to the bone so I could have a better life and sometimes I feel guilty even wanting something like this you know? Like maybe Im asking for too much. But four years? Thats not just shy that feels like avoidance. Last month his cousin got married and he went alone. I asked why I couldnt come and he said it was just a quick family thing. But he posted pictures with all his relatives smiling like nothing. I just sat at home eating takeout and feeling invisible. Am I being unreasonable to want this? Or is this a red flag I’m ignoring?