Hearing about boyfriend’s family events makes me sad about my lack of family

My boyfriend and I are in our early twenties. He has a very very close family unit and a large extended family that lives near him. I have no family in my state other than my parents and brother. I am estranged from my mom’s side of the family (she is as well) and we see my dad’s parents a couple times a year. There is a lot of family trauma and unhealthy dynamics.

My partner talks about his large family dinners and events and vacations and parties. I am happy for him and those should be positive things and I want to express my excitement for him, but when I hear about it it makes me want to burst into tears. I just have no experience of close family relationships.

I haven’t shared this with him and I just offer fake statements of excitement and hide any negative emotions.

I just wanted to vent because it makes me so sad yet I don’t want to kill his fun every time he talks about a large holiday gathering.