WMG / Three's Company

Mr. Furley knew Jack wasn't gay from the "Baby, It's Cold Inside" episode to the end of the series.
Towards the end of the series, with this episode, Jack, thinking they were both dying, told Furley that he wasn't gay. After they were subsequently rescued, Furley relayed this to Larry, Janet, and Terri. He said that Jack was delirious, which made him say this. But, in the episodes following this one, the gay jokes were fewer, and the ones that were there were usually followed by a "just kidding." Also, during the final episode, before Jack tells Furley that he's moving in with a girl, Furley is obviously within earshot several times of Jack and Vicki and their situation. He's one of the ones listening to the conversation in the kitchen during Janet's wedding. He just didn't let on that he knew because he saw Jack as more of a friend/son from here on out.
  • And he couldn't just come out and admit he knew the truth. In an earlier episode he said if his brother (who actually owns the building) found out Jack wasn't gay then he would make him kick Jack out.
  • Not to mention the loss of money while the girls struggled to make up Jack's part of the rent until they found a suitable roommate.

Chrissy Snow suffers from some sort of neurological disorder that ultimately kills her.
Early in the show's run, Chrissy is portrayed as rather naive (not surprisingly, being both a country girl and a pastor's daughter), but was otherwise a normal adult woman. Beginning in the second season of the show, Chrissy began to show signs of not being particularly bright. As the seasons passed, Chrissy's mental capacity continued to diminish (as illustrated by becoming easily confused and making nonsensical statements that only make sense to her). Jack and Janet do their best to care for her and humor her bizarre behavior, but they realize that they cannot give her the care that she needs. Eventually, she reaches the point where she could no longer live on her own, or at least under the care of Jack and Janet. She is sent back to Fresno to live with her parents; in the confusion of the move, she believes that she is going home to take care of her mother, when it is the other way around. Eventually, she loses contact with her old friends, having reached a state of deterioration whereby she can no longer remember them. In the final episode, she is notably not invited to Janet's wedding, an event for which someone might expect her to be present. She doesn't attend, because she is either so far gone mentally that it would mean nothing to her, or more tragically, whatever condition she had has killed her.
Mr. Roper is gay.
He displays no interest in his wife, not even when they were young newlyweds. He buys porn magazines, but hides them where his wife is likely to find them. He tries to hit on women, but can't figure out how to interact with them. He's afraid of Jack, who he believes is gay, and taunts him constantly about this—oftentimes the reaction of a deeply closeted homophobe.
  • This would only make sense if he has any more of an affinity for guys. Asexual characters (or characters with less of an interest in sex) were a much more popular staple in the older days of sitcoms.