Ron Davis (played by Jay Tarses) is a friend of Steven and Elyse Keaton. Ron and his then-wife Suzanne met the Keatons on their honeymoons and have been going on anniversary trips together ever since. Shortly after they met, the Davises beat the Keatons in the potato sack race. Ever since then, Steven and Ron have been extremely competitive at games and sports, to the point of it affecting their marriages. The Davises have kids, who are in college as of Suzanne Takes You Down.
In Not With My Sister You Don't, the Davises and the Keaton parents go on vacation together. Steven and Ron's constant competition irritates their wives.
In Suzanne Takes You Down, Suzanne reveals that her marriage with Ron has been on the rocks for the last thirteen years. Sure enough, later in the episode Ron decides to leave Suzanne. Over the next few weeks, he enjoys his single life and gets into skydiving. Then he changes his mind and asks Suzanne to take him back. She refuses.
In Anniversary Waltz, Elyse says that Suzanne said that she and Ron are both coming to the Keatons' twentieth anniversary party (although we don't actually see them at the party). This suggests that they're still in close touch and may even have gotten back together.