Want to be a police officer but wife is scared?

im married and im 24 years old i work at walmart i have never been a person that has ever liked staying in side all day, so im not happy i have been geting in shape im 6 foot 2 i have went from 250 pounds 215 pounds my wife think that i have been just trying to get healthy and lose some pounds but i have been training to be a police officer thats what i have always wanted to do with my life but just saying anything about it to my wife, makes her cry she thinks somethings going to happen to me. before she was all about it but a friend of mine was hurt on duty someone we went to school with and that changed. we have no kids in are lifes what do i do