Question about living in Madrid

I can't find an answer anywhere online but....I'm american i moved to Madrid 3 months ago who do i tell i moved like I just packed my things kissed my mom good bye amd left i am married to a Spanish women I already have my NIE CARD BUT SHOULDN'T i tell the American government I live here i went to the embassy website couldn't find any help is signed up on the STEP WEBSITE that was useless too like don't i still need to pay American taxes um what if I get jury duty back home amd don't show up then I'm in trouble I'm really confused like seriously is this not important am I stressed for nothing like legit i packed my stuff hopped on a plane and came to madrid 3 months ago got my Spanish green card got a job all is good but I'm thinking someone besides my mom needs to know right?