Because an FSA can be used to pay for the expenses of a spouse, it counts as "other coverage" that disqualifies you from making contributions to an HSA, even if you say you won't use the FSA money for your own expenses. This is true even if your spouse removes you from the insurance coverage, the FSA can still be used to pay for a spouse's expenses.
If the "qualifying life event" would allow your spouse to drop the FSA entirely, then you could make contributions to an HSA. Or your spouse could change to a "limited purpose" FSA or a "post-deductible" FSA instead of a regular FSA (if the employer allows). Those topics are described in more detail in publication 969.
https://www.irs.gov/forms-pubs/about-publication-969
