I think I found out that it's not separation anxiety. At least not entirely. It's more like whenever his schedule gets upset. Because I tried a couple of things and everytime I did something different, Bandit would pee on the floor. So, now I've been tying Bandit to the bed nightly. So far, so good. The first three nights of this, he would pace when he had to urinate, I would get up, take him out and he'd do his thing. Then back on the "bed leash" to sleep for the rest of the night. After those first nights he went back to normal routine and would sleep right through without a hitch. Last night, he asked me to let him off the leash, so I did and he went for a snack instead of wanting to go out. I denied the snack, put him outside instead. Back in and back on the leash. No problem.
:) Yay! I am liking this. This weekend, we have to leave Bandit alone for two days (one night). My friend will check on him, but it will upset him for sure. So first night back, I'm going to make a point of getting up, even if he doesn't ask and just pet him. If he wants out, fine, but I'm not going to initiate that. <fingers crossed>