My mom passed away 11 years ago. Currently, my dad has a girlfriend who I've met several times but not really spent much time with. So, I'm not really close with her. My question is what is the etiquette on where she would sit. I don't really want her sitting where my mom would have sat because some people on my fiance's side don't know me really well may think that's my mom. She's definitely not going to be escorted in. I was thinking of having my mom's sister sit in her place. Any advice?