That kind of production was known to take a toll in general, IIRC, being one of only two main cast (and the lead) on the original Quantum Leap led to Scott Bakula's first marriage falling apart, and by later seasons he actually had in his contract that he was leaving the studio by 4PM each day or something like that. I suspect this might be a reason why those kind of shows, with only two in the main cast going for over twenty episodes just aren't done in American television anymore. I think the last such show was Supernatural, and even that eventually added more to the main cast.
Even in the streaming realm, the only American show I can think of with only a cast of two is The Last of Us, and even with less than ten episodes, they still do the Doctor Who thing of a "Joel Lite" or both "Joel and Ellie Lite" episodes. Granted, the Joel Lites might be necessitated by the fact Pedro Pascal is something like twenty projects on the go simultaneously.
Even in the streaming realm, the only American show I can think of with only a cast of two is The Last of Us, and even with less than ten episodes, they still do the Doctor Who thing of a "Joel Lite" or both "Joel and Ellie Lite" episodes. Granted, the Joel Lites might be necessitated by the fact Pedro Pascal is something like twenty projects on the go simultaneously.