Because active Sagittarius works out more than most, you may have developed muscles in areas other people haven't. Off the rack clothing may not always fit you as a result, particularly in the hips and thighs. It's not you!
One size doesn't always fit all, so thank goodness there are tailors. Knowing that an exact fit can be tough, and you can try things on without thinking that your body's somehow at fault.
That doesn't jibe with Sag's live and let live aesthetic. Accepting your body means working with a skilled tailor who can help make you look fabulous all the time.