[DvlshAngel985]

I thought it was unusual because he came from a home with lots of other doggies, and for him to make such a huge mess of himself when he wasn't completely alone has me baffled. He's comfortable around Danger when I'm there, I did have to teach him to have a little self control (through repitition) but otherwise these two get along nicely. I've heard him cry and whimper when I leave him alone upstairs, but what I try to do is not reappear until I hear he is quiet and I make him sit nicely for me before I let him out of his expen. He knows now that he has to sit and wait to be invited out before he can roam around.
He's 1 yr old, so he's not a puppy that needs to much training. He just had a problem with leg lifting, or marking, in a house that smells like another dog. He's so smart too... in a few days he understood no leg lifting inside, because I watched him closely and corrected him (clap to interrupt followed by a "NO") everytime I saw him try to lift his leg. But at home with my parents, there are no other dogs so he never even tried to lift his leg. This was the weekend immediately after his neuter. He peed and pooed nicely when I took him outside just like a pro.
I think what has me confused is the part where he seems fine when alone yet when he was with the other dog he was a mess. Plus, when I called the vet to check in case he had a UTI, she said it definitely sounded like seperation anxiety.
Should I not leave him alone with the other dog? Was the other dog's company more harm than good? Am I being a neurotic new mom?