When referring to a romantic partnership it would just be "a couple", not "a couple of people". The latter would be interpreted as a group of several where I am.

It's the phrase "a couple of blocks" that was under discussion. And then "ask me for a couple of something and I give them exactly two." Couples of people didn't arise until you shoehorned them in.

how often have you referred to a romantic couple as "a couple of people". What if I say "A couple of people attended my party", does that mean a romantic couple showed up and no one else?