If you want realism in romance books, then nothing much is gonna happen. Just sayin'.
Because while Real Life can be stranger than fiction, for the most part it's relatively boring. Even historically, it would tend to be boring. The ton (which compromises 99% of the historicals written) do the same things day after day. There wouldn't be much contact with spies, women wouldn't cross dress, etc., etc.
There are, of course, exceptions to every rule and I'm sure some erudite soul could point me towards proof that such things indeed happened. But people like Lady Hester Stanhope stand out precisely because they are so different from the norm of their times.
(Btw, is ton singular or plural?)
Reality for most of us is doing the same things every day for most of our lives. Get up, go to work, come home, get supper, go to bed. It's why vacations are so coveted - something different!! Even jet setters can get bored with party after party. Always the same people, always the same thing.
And I think it's why romance fiction can be fantasical, historically incorrect, and downright outrageous sometimes and still find an audience.
Screw realism. Just entertain me and offer me a well written escape when I need it and I'm yours for life.
Oh lord, I suddenly feel the urge to read Naked in Death again.