Could this relationship be realisic/healthy?

So (I'm just making up random names for the sake of staying simple) Betty and Bill have been married for several years, but neither entered the marriage willingly and essentially the reason they are still married is due to their society's taboo on divorce and for the sake of their (fully grown) children. They are rarely emotionally/sexually intimate with each other, Bill sleeps with other women on business trips, Betty (correctly) assumes this is the case, but is okay with it.

• Betty meets Freddy, a widower who hasn't remarried mainly due to the fact he still hasn't gotten over his late wife (it's been about 10 years since her death) was one of his few close friends and also was a coping mechamism for his social anxiety. Freddy and Betty hit it off while Bill is off on a trip. Freddy is attracted to Betty, but resists the urge to act on it due to the fact he is anxious and she is a married woman. She begins to persue him and eventually shocks him greatly when she suddenly kisses him. He immediately freaks out and tells her that he believes that being in a relationship with a married woman is morally wrong. She admits that she knows that Bill engages in extramarital sex and believes that, due to the fact neither of them are 'into the marriage', the cheaing isn't as bad. He doesn't agree, but then realizes he's still nervous about his former wife, but evetually lets her go. It temporarily stops their relationship, but they become" friends' again
• Later Betty and Bill finally get a divorce on good terms. At this point, would a healthy/sucessful between Freddy and Betty be plausible?

I dont see why not. Both were honest with each other and dealt with their attraction in a way that was consistent with their own values.