Seinfeld- Jerry and Elaine are exes and breify get back together at the end of season one

Friends- lots of romantic entaglements but mainly Chandler/Monica, Ross/Rachel, and Joey/Rachel

How I Met Your Mother - two of the main characters are a steady couple, the other three are a love triangle

Big Bang Theory- by the end, it’s three couples and one single guy

Any shows like these where the main characters never date each other or hook up with each other?