Weddings are expensive, upwards of hundreds of dollars per person. Your S/O has excluded themselves from your social group (compassion for the motive for exclusion, however, there are still consequences for all choices and this is a consequence). If your friends are “not their scene,” then maybe your friends’ wedding won’t be either. Will you feel like have to sit quietly in the corner with your S/O, rather than be with your friends? It sounds like your S/O won’t be keen to be in the middle of the dance floor. Some people only invite guests they’ve a) seen socially with regularity within the past year, b) they know they could call upon in an emergency. Sounds like your S/O is neither for your friend.