Something something, Bridgerton AU with Duke/General Zayne and he marries only to do his duty. For political advantage only, resigning himself to the fact he will not, and does not intend to find love. He marries a suitable enough lady, thinking the most interaction he's going to get with her is at formal events and the occasional passing each other in the hall.
Imagine his surprise when the woman he married just refuses to leave him alone. She's following him everywhere. Whether it's in his study, him carrying orders, training men or paying visits to important people, she is there. Questioning him, challenging him, daring him sometimes to do send her away. He doesn't.
She has no sense of propriety, growing up in a household warmer than his, noisier than his too. Traditional customs that noble ladies should follow? Out the window, she is following that man no matter what he says or does. She has an answer for everything, isn't put off by his demeanor, and the first time she visits the estate garden she finds a stray cat and decides to name it after him ("Duke" if we're going for him being a Duke route).
He should be apalled, mortified, regretful, whatever. He isn't. It's much worse, he's falling in love.
Now he has to deal with that fact, that realization. In classic Bridgerton fashion though, he realizes this after he's broken her heart/offended her/just royally fumbled in general. Maybe he snaps at her, sees her attempts to at least make this marriage enjoyable and tells her straight to her face he does not and will never love her. That their marriage is a mere transaction to him.
Cue him begging on his knees for her forgiveness. Maybe she decides to leave, to live in seperate households and he corners her just before she can go. Wet, pathetic dog energy because so far he has been so damningly composed, and now he chooses to let it all out.
Or or maybe it's during a ball. Another lord, some insignificant baron, tries to make a move on her - a married lady - and he comes in behind you to glare at the man in silence until he leaves her be. Then he's dragging her somewhere to hash out all the complicated feelings he's been too good at ignoring lately.
Doesn't even need to be angsty, just one of those 5 times bla bla bla and 1 time he did something about it.
Will I write about this? Yes. Will it take a while? Absolutely.