This happens to my spouse and me very often. We've gotten pretty good at noticing after the second "I dunno, what do you want to do" round that we need to switch from ask mode to tell mode. Don't give options, just propose something, and say "any objection must take the form of a counterproposal" (yes, we say literally this sentence to each other a few times a week).

Especially when one partner is more tired than the other, we can instead just have the more engaged partner pick something and the tired one get one or two vetos before being forced to step up and actually accept something. This isn't always comfortable, especially when it's unclear that there exists a good solution.