Thanks for your response! Otto is probably a pointer mix of some sort. I posted his picture in the Breeds forum, and a lot of people guessed that he might be mixed with Heeler (another breed that tends to connect with one owner).

The boyfriend tries to play with Otto, but Otto is just completely disinterested. After lots of trial and error (he's a picky little guy), we've discovered that Otto likes turkey hot dog pieces as treats, and my boyfriend has been using them to try to get Otto to walk with him, but it isn't too successful. Thankfully, Otto will do some training (sit, lie down, stay, and come) for treats, but it hasn't seemed to help him take to the bf. We'll keep up with it, though!