He spent half his life at war and only went back to his hometown in old age.
Tips
usage
戎 means military, as in 戎装 (military dress), so 戎马 is the horse of war and by extension a soldier's life. Common phrases: 戎马生涯 (a military career), 戎马一生 (a lifetime in the army) and 戎马倥偬 (always on campaign, with no time to rest).