I'm sure this issue has been covered before but I can't find it.
I am inviting a group of college friends to the wedding. 2 are married, 2 are in serious relationships (but not living together), one is single. I have only met one husband, none of the other SOs. I am definitely inviting the husbands, but do I have to invite the boyfriends? If it makes a difference, the two friends with the boyfriends are best friends, so they won't feel uncomfortable traveling without their partners. I'd just like to follow proper protocol - I don't think my friends would be offended.
Thanks for the input!