Social anxiety is ruining my marriage ?

I've never really been around my husbands family .. me and his mom are really close but she lives in another state and we only talk by phone . I've only been brought around his family once (he's not close with his family) and that was at his step moms birthday party . I'm an introvert .. I get really bad social anxiety and I hate being the center of attention.. if I'm nervous I sweat my face gets red and I studder. He keeps inviting me to things and I always say ok sure but I'm so quiet unless people talk to me first ... and i honestly don't feel like he's trying to make me feel comfortable around people ive never been around. It's probably because I don't have family of my own and I don't really understand . But tonight i told him I wasn't feeling well to not go to his aunts house warming . How can I get over this? I hate this