Posted: 18/10/2015 at 14:07
What Dave said... you also need to know (esp if you have done little cycling before given that you don't own a bike), how to go down a hill efficiently, climb efficiently/comfortably, corner efficiently (ie be comfortable RIDING a bike), know how to use gears and brakes, get used to the bike you are using as well. It's not just about sitting spinning your legs. Surely your wife would be more comfortable with you riding 110 miles when you've actually ridden a bike before and not just getting on on race day in amongst crowds of cyclists.
p.s. You are an adult, you don't have to do everything your wife says. Buy a bike and get out on it. (Get fitted for it first, make sure it's semi-decent if you are planning an IM).