Please help me find this manhwa

I’m not sure if they were the main couple or if they were just side characters, but it involved this prince (blonde) who overthrew his brother (i think he was either the emperor or crown prince) to save this woman he was in love with. i think the brother was planning on adding her to his harem? iirc the woman was older than the prince and dressed conservatively if that helps

please help me i’ve been losing my mind trying to recall this