回複：入籍離婚，再婚

The problem is 一年分居 already started before you filed N400 based on 3-year living with Citizen spouse? To be specific, you claimed 3-year union but in fact you were separate? This could be a serious problem.

If that is not the case, your US citizenship is solid. And you can sponsor a spouse GC after 5 years of your LPR(or conditional PR) approval.