When friends are divorcing, who do you invite to your wedding?

For a wedding next winter, why are you trying to figure this out now? Since these are your fiancee's friends, it's probably her call, but she's got months to figure it out. It's not uncommon for early versions of a guest list to have a couple of question marks, so if it was me, I'd allocate two spots for them, and see how it shakes out. You don't send invites out until 6-8 weeks prior to the wedding, and I'd think you'd know a lot more by then.