I wouldn't do this at all unless you both intend that you take a role in the business. For a start your home address will become the registered address for the limited company, which means all the stuff from Companies House, HMRC (PAYE and CT) will come to you. Plus all the junk mail.
Limited companies have to have public liability insurance and that will have to be displayed at your house as well (should look nice in the kitchen next to the clock, I suggest).
If he doesn't administer the business properly, you could be liable as a director for the maladministration (though your fiancial liability would be limited to your stake, which I assume would be nominal.
This is not the way Companies House intend that businesses are set up.