Retired Tech Sergeant David Simpson had to leave his job as an Air Force M.P. for medical reasons. During his tour of duty in Iraq he spent four years with Robby, a German Shepherd military dog. The two patrolled streets and conducted security checks at military bases.David retired while Robby was still on active duty at Spangdahlem Air Base in Germany.“[It’s] probably the most difficult task we have to do, other than having your dog passing away,” Simpson told FOX 13. “It was very tough to go through, and you don’t know if the dog understands. Having to say goodbye, that is heartbreaking.”But now the pair are back together again. A year after saying ‘goodbye’, David received a message saying Robby was due to retire. There wasn’t any question in David’s mind what to do next. He boarded the next possible flight to Germany to reunite with his partner.“My goal for him is to allow him to have as much fun and relaxation for the rest of his life. I just want him to enjoy his retirement,” David said. David has since taken Robby home to join his family, including his three young children.