Hi. I would practice good discipline on a lead. I would only let a dog off if I had complete control, if your partner is the one who does the walking then he will be the one who has control. In order to get control you need to practice disciplined walks on a lead, ensuring he is walkiing to a heel. Practice the recall in the garden and house and then move to doing it outside. If you are stepping in temporarily then just do disciplined lead walks to establish yourself as the boss. Hope this helps x