We have occasionally thought about bringing in a second B, which is shocking because most of our first year with Ella was so hard. But the second year has been so good it has become a fleeting thought. But the description you gave of what happened with Cassie and Alex is exactly our fear. Ella loves to meet all other dogs on walks but is pretty submissive and I have a feeling she very well might get bullied by a new pack-mate.
We think about it because Ella also stays home alone for much of the day 4-5 days a week. But I do not sense that she is stressed about it at all. She sleeps in the sun or looks out the windows most of the time. I usually have to wake her up when I come home for lunch and at the end of the day. When I am home during the day she pretty much ignores me and sleeps in the sun and looks out the window anyway. After the novelty of a new dog wore off, I think she/they would still do the same thing each day.
The thought I have is, if you get a second dog do it because YOU want a second dog. Don't do it because you think that is what your dog wants.
