HaBO: Everything But the Names

You did it! We figured this one out! It is a truth universally acknowledged (by me for certain) that the Bitchery pretty much knows everything, and really, it's true. Scroll down to see the solution for this HaBO - and many thanks!

Marisa has the same problem I do: she remembers a ton of details, but not the names of the characters or the title of the book: 

I am looking for a book I got from the library forever ago and can't find.
Of course, I can't remember the title or the character names, but I can
remember some other details.

 

It's historical and in England, but I'm not sure when. It starts off with
the hero at the church after a failed marriage attempt. (The girl was in
love with someone else, so he let her out of the engagement, much to the
annoyance of her family.) He has been trying to secure a wife for a while
now. The heroine comes in and offers herself for marriage, citing some
reasonable argument for why he should accept even though he doesn't know her
(dowry?). He accepts, they get married and go off to live in his big house
(he has some kind of title). I remember she has this little dog that she
takes nearly everywhere.

They have this awkward first night where he comes into her bedroom, assures
her this will be over soon, takes her virginity, and then leaves. It is
revealed to us that the heroine is not a virgin, but had a secret engagement
to a man who ended up not wanting her, but not before she got pregnant. She
had a big plan to go off and live with the baby far away but she miscarried
after a couple months. However, since all of this, she had fallen in love
with the hero from afar, which is why she proposed marriage to him in the
first place; but right now she has to figure out how to get the hero to love
her and figure out why the hero won't sleep in bed with her.

 

Hero won't sleep in her bedroom because he has PTSD (ex-soldier/spy?) and
has to sleep in the corner of his bedroom on a pallet on the floor, so that
no one can sneak up on him and kill him. Heroine later finds out and is more
than happy to sleep on the floor so long as she can be with him.

Other things happen, all I can remember is the climax comes when the villain
has the heroine on a roof, and is about to throw her off when the hero comes
and saves her. There is also a small side romance between the hero's
butler/manservant and the heroine's maid. This is also the first book I can
remember finding the word “cunny” used during sex.

 

ALSO there was another small side plot about this mistress that the heroine
meets in the park (heroine's dog and mistress' child play together). Near
the end, the heroine ends up helping the mistress flee the city by sending
her and the child off to a friend of the hero's whom we met earlier in the
book, who lives in an old, unkempt mansion (/castle?) and is very mean and
grisly so that no one ever comes to see him except the hero. I think he also
might have an eye patch or big facial scar. I think this might have turned
into another book.

Isn't it sad how I can remember all that but I can't remember anyone's name?
Thanks for any help you can offer.

 

Anyone remember this book? Or the sequel? That's a lot of detail, so I'm betting someone will recall it.