What do you do when you have a partner who doesn't listen??

Ok, since day one of owning Ashley ( she was my x-mas present ) I INSISTED she be on collar and leash in the front yard. We have a so-so busy street, but I know at 4 months if she see's something interesting..she will bolt, and all it takes is ONE car driver caught off gaurd.
I have tried everything I can think of to re-inforce this to my DH, but he refuses to LISTEN!! I just caught him out the side yard with the puppy..off leash as he wheeled top soil into the back-yard. I yelled for her to come ( of course being protective Mommy ) and he yells at ME that she is fine..that she is listening to him, and following him around.
I am SO angry..I told him, "if you LOVE her like you say you do...you'd leash her ALWAYS!! ". Now not only am I hovering around the back yard fence opening and closing it for the big oaf ( DH..not Ashley! ) but I have to give her a full bath, as he thinks its funny that she is jumping up and biting the soil as he spreads it..she is dirt from head to toe!! Grrrrr!!!!
Any suggestions besides hiding my baby girl when he goes outside?? ( I know his one and only other dog was picked up by the pound and died along the way due to heat stroke...you would think THAT would deter him from letting her run free but NO!! Is he a block-head..or what?? )