My boyfriend never comes to family events with me

My boyfriend and I been together for 3 yrs and my family has just recently started to meet him this year. Anyway, my grandfather told me to invite him over for Christmas to which I gave him an excuse and said “well grandpa he usually spends the holidays at his own grandparents house”which is a lie. For every family event I invite my boyfriend to he never wants to come no matter how much I beg them . The only way he’s ever met members of my family was in quick moments that never lasts more than 10 minutes besides my mother . Granted , he barely goes to his own family events and the last time he went to a family event of his was the 1st yr of our relationship. I just feel so much anxiety when my family brings up barely knowing someone I’ve been with for 3yrs and their quick and short meetings and then having to make up lies to excuse him. I asked him if he could come to Christmas to meet my grandfather and he wouldn’t have to stay the whole time he could stop by for 20 mins and I would excuse him and say he was spending the rest of his holiday at his grandmothers but he said no to that... what should I do ? It’s bothering me