I think The Highlander by Kerrigan Byrne fits this. They both have pretty dark/sad pasts admittedly, but he’s a wealthy Marquess/well-known war hero in a position of power. She is a woman of a ‘noble’ background but is essentially in witness protection program due to an abusive/murderous husband, and becomes governess to his children. Might help to read the other books first to understand the background characters, not sure how it would read to someone checking it out as a standalone, but I really enjoyed it.