Non Jews at holiday gatherings

As Pesach approaches I’ve been wondering a lot about the role non Jews can play in Jewish life.

My fiancé isn’t Jewish. He’s embraced Jewish culture entirely, he actively celebrates every holiday, has attended services with me, has visited Israel to see my family, and our upcoming wedding is in Israel and his whole family will be flying over to attend (legal ceremony won’t be in Israel obviously due to interfaith marriage laws). He’s obviously active in Jewish life, he just hasn’t undergone official conversion. And he has no plans to.

I’m not particularly religiously observant but I do know that there are some prohibitions regarding non Jews attending Yom tov meals (and possibly services, I’m not sure on that one). He’s celebrated holidays at Chabad in the past however I’m starting to worry whether that’s acceptable. We’d really like to attend again this year but I’m not sure if that’s putting our local Chabad in an uncomfortable position.

Has anyone had these concerns in mixed faith relationships or families?

Thanks!