I've only had one so far, at 8 weeks. I have one on Monday at 18 weeks for my anatomy scan, and as far as I know that will be it for ultrasounds! My husband came with me to my 8 week one and is coming to my 18 week one.
After I found out about the anatomy scan though, my mom asked if she could come because she said all her friends told her that they all went with their daughters to at least one ultrasound and you just have to "meet" your grandchild before they are born, etc. I don't really care either way so I told her that was fine if she wanted to come. Which she told my dad who then assumed he was invited and when my mom clarified he said he really wants to come and meet his grandchild too. I asked my husband and he didn't care, and I didn't care-- so it's a plan.
I just called the ultrasound center to verify that is allowed though (to have more than 1 person with you) and the nurse said it was fine but honestly sounded really weirded out-- like this was a super uncommon question/request.
So-- wondering! Did you ever have anyone but your SO go with you to an ultrasound? Parents? Friends? etc?