Historical romance novel

Hi! Please help me find a book I read as a teen. It was a paperback and I’m almost confident the title had something to do with wedding/bride/arrangement. The book starts with a bride and her new husband: they are separated immediately after their wedding due to his being involved in a war or some type of activism ( I want to say he is Scottish, or Irish.) It takes years for them to reconnect, and when they do, he wants a divorce, but she wants a baby. He agrees to give her an heir before they divorce and much of the book focuses on them rekindling a passion as they try to conceive. Aside from those details, I remember that the grooms sister was described frequently as being ‘Fay’ (which I only remember because I had to look the definition of it up) and there is some type of negative history between her and the son of a family living close to the groom. I also believe that the bride fakes her death or is assumed dead towards the end of the novel. Please help with this, it is driving me crazy!