All right! This is completely embarrassing, but I need help finding a story! It is a Harry Potter/omc slash fic, where Harry is forced by someone (his mother, lily, I think) to marry an older man. Sirius is alive and supportive of Harry, and Harry is required to get pregnant for the man. (yes, it is mpreg). The man seems cold and uncaring for Harry but gets better as the story progresses. Oh, and I think Harry might be allergic to something, and then a person (I know, I'm very good at remembering details) tries to poison him. The allergy might have been to fish?
If anyone could review with the answer, I would be most grateful!