I hear you. The whole idea of the 3 of Cups as a "third party" card has definitely mushroomed on social media, but it's not how I usually read it either. To me it's mostly about friendship, celebration, community, and emotional support — being around people who lift you up.
That said, context matters. If the 3 of Cups pops up next to cards like the 7 of Swords or the Devil, I’ll consider hidden dynamics or outside influences. That doesn't have to mean another person though — it could be work, stress, old patterns, whatever is affecting the relationship.
Alone, I don't jump straight to "third party." I read it as a positive sign of shared joy or a nudge to reconnect with your circle. It can also be a gentle warning that you might be over-socializing and need to shift some energy. So yeah, the third-party angle fits sometimes, but it’s not my default.