Hi,
honestly, i think your missing your point. You need to really calm down a bit, and maybe even consider going for a fiance visa with your husband if you can't sort out the requirements.
I seriously think that their question is more about why you are willing to leave your business for three months, why going to the uk for three months and what reasons you have for returning. And no letters will help you with that, you need evidence and proof.
Relax and think things through carefully, before spending more money.
