Odd couple = strange hubby and wife?

Well, yes, it could imply that. However, there was a successful play on Broadway in 1965 by Neil Simon entitled The Odd Couple about a pair of bachelors--one slovenly and rude, the other prissy and obsessively neat. The play was made into a movie in 1968 which was very successful, and it eventually became a television series.

So, in American culture "odd couple" means a glaringly mismatched pair.

Set is correct.

You've run into another phrase, "the odd couple", that needs to be considered as a whole.

Thank you both

And English speaking culture generally.

perhaps the author refers to a potential nexus between the two

unless everything is a throw away line