To make it hard to quit they got a dog together. It's supposed to be the company's dog, not either of theirs
individually. The idea being that now the company can't go away or there's no one to take care of the dog. Increased the burn rate a little but turned out to be a net win.
I know it's not really the same situation, but this reminds me of couples who have a child to help protect/save their marriage. This usually hurts, rather than helps the marriage.