Constant whining

Hi everyone,

I couldn't find anything specific to this problem so posting to get some help. I have an almost 3 year old lab-australian sheperd mix breed dog. He has his issues but this has to be probably the most annoying. He is a very vocal dog in general demand barking etc… but lately his whining has gotten out of control. Its constant, if he is not sleeping, eating or outside he is whining. The weird thing about it though is if I am alone with him, he is generally more quiet, only whines when it's time to go outside. My husband has the same experience, when he is alone with him hes generally quiet and sleeping. But when my husband and I are together, its CONSTANT whining. It never stops. Its like he cannot see our sitting/relaxing on the couch. Even when we try to engage him and play together, he will play for a few minutes then loose interest and start whining. He dosnt have any new medical issues that we are aware of that could be contributing. Has anyone experienced this before? We have tried ignoring him, leasing him and making him lay down infront of us, even using a soft muzzle for short periods of time and nothing works. I need help! I am going crazy!! Thank you in advance