Most people have a "type": A certain set of features that they find pleasing in a romantic partner. But some TV characters don't just have a type, they want to date someone who looks exactly like their dream guy or gal. These TV characters can't be with the person they really want. Instead, they date a person who looks eerily similar to someone from their past.
Cesare BorgiaShow: "The Borgias"
Dated: Ursula Bonadeo
Who was just a poor substitute for Lucrezia
There's a very good reason Cesare can't be with Lucrezia: She's his sister. Even in medieval Italy, that's not okay. After dancing with Lucrezia at a wedding, Cesare meets another dancing blonde with curly hair. Her name is Ursula Bonadeo, and Cesare falls madly in love with her. Unfortunately, she's already married.
Frasier CraneShow: "Frasier"
Who was just a poor substitute for Hester
The sad thing about Frasier's short-lived relationship with Mia is that he doesn't even realize he's dating someone who looks just like his mother, Hester. Until it's pointed out to him, Frasier doesn't understand that what he is seeking from Mia is a sense of warmth, comfort, and protection. It probably doesn't help that Frasier seems to have some unresolved mother issues.
Dated: Nina Ash
Who was just a poor substitute for Buffy
Angel and Buffy are soulmates, but they can never be together. Every time they try to get together, Angel turns evil because of a curse that was placed on him. So he leaves Sunnydale and Buffy behind, and eventually takes up with another doe-eyed blonde chick with superpowers. Sadly, Nina couldn't make Angel perfectly happy.
Dr. Temperance BrennanShow: "Bones"
Who was just a poor substitute for Agent Seeley Booth
Booth and Bones did eventually get together, but it took years. Back in the show's early days, Dr. Brennan felt that she couldn't date Booth because of their working relationship. Sublimating her desire for Booth, she starts dating Agent Tim "Sully" Sullivan, who is similar to Booth in many ways. Both Sully and Booth were athletic, dedicated to their work, fun-loving, and the two even looked a bit alike (although Booth definitely had the better haircut).
Rachel GreenShow: "Friends"
Who was just a poor substitute for Ross Geller
In one memorable episode of "Friends," Rachel's latest boyfriend is a guy named Russ. Not only does his name sound similar to Ross, but Russ also looks just like him. They sound alike, act alike, and even look alike (except for the hair).