Do You Have to Invite Someone to Your Wedding Because You Were Invited to Theirs?
There are certainly lots of people you don't have to invite to your wedding that you shouldn't feel bad about. But here's a sticky situation (especially if you happen to be a people pleaser)—what do you do if someone invited you to their wedding, but you're not particularly interested in inviting them to yours? In our opinion, you don't have to reciprocate the invite if any of the below apply.
You don't know why you were invited in the first place.
Maybe it was a random sorority sister or a "satellite friend" who you never really see outside of group settings—and you were a little taken aback when you received their invite originally (and, perhaps, didn't even attend their nuptials). It's certainly not required for you to extend the invite if you've never really felt close with this person to begin with.
It was years ago, and you've grown apart.
If their wedding was only a little around a year ago and your friendship hasn't changed since then—then yes, you should probably find a way to squeeze them onto your guest list. On the contrary, if the wedding was three or four years and you haven't really kept in touch, then no, an invite isn't obligatory.
Your wedding is extremely intimate (and theirs was huge).
Different sized guest lists (like different sized wedding parties) will require different cut-off points. Maybe they had an enormous black tie affair at a massive ballroom that fit 300 people—and you're having an intimate backyard wedding with less than 50 guests. They'll likely understand.
You're not inviting the group of friends or acquaintances you share.
It's important to tread lightly here. If this is a friend from work and you're choosing to invite all of your other colleagues, then it will definitely come off poorly (and, at worst, like a personal dig) if you leave this person off the list. But if you've decided to omit coworkers entirely from the guest list, then they're more likely to understand when they don't receive an invite.