You getting new coverage and becoming eligible for some kind of DCFSA with match at a new employer would probably be a qualifying life event. That’s not what happened though. No family members are being removed or added to the benefits. You just want to reduce them. Unfortunately, that’s not how it works, and if they did it, they would risk losing the IRS tax exemption on the whole plan.

You losing insurance coverage from your employer would also be a QLE that would allow your husband to add you to his coverage. If you were already on his insurance, you quitting your job is not a QLE, because you’re already on his insurance. You didn’t lose that coverage.