I deal with this too.
My SO is not on board with training, at all and does not want to become involved.
So.....here's some things I did, hope these tips help you out as well.
I lowered my expectations for hubs. He's just not into training or any real obedience. He just likes to 'play' with them letting the dog pull him down the street on leash is fine with him. So I drilled into him just a few basic safety rule type things. Not allowing door dashing, practicing recall for safety type of things. Breaking out only the really important commands for safety made it seem reasonable to him so he was willing to work on those things.
I also trained the more formal commands using German which he does not know. So when I give commands it's clearer to the dogs what I want and what I mean. This way when hubs is outside telling the dogs to do something he's not 'diluting' any of my commands where I train for snappier response and reinforce consistently. He can say 'down, down, down, down, down' as much as he wants and neither I nor the dogs care. When I say 'platz' they down, also command for loose leash walking. So when he walks they can pull if they want as they are basically 'released'. When I walk I give a command and they have a 'position' that they have learned to stay in. So that helps a lot too, I can just watch and smile ..."down, down, down, down....down.....down........"