Both Sides
You can marry anyone who is the opposite sex of you.
Azura your songstress and you get her on both sides.. She can marry Corrin, Jakob, Silas, Kaze, Ryoma, Hinata, Subaki, Takumi, Saizo, Hayato, Kaden, Azama, Xander, Leo, Odin, Arthur, Flannel, Benny, Laslow, Niles. His list is long because he is on both sides.
Jakob is your butler and you will get him later in the game. He can marry Corrin, Felicia, Mozu, Azura, Hinoka, Sakura, Hana, Orochi, Rinkah, Kagero, Oboro, Setsuna, Camilla, Elise, Berkua, Effie, Nyx, Peri, Charlotte, Selena
Silas is your best friend and you will get him early in the game. He can marry Corrin, Azura, Felicia, Mozu, Hinoka, Sakura, Hana, Orochi, Rinkah, Kagero, Oboro, Setsuna, Camilla, Elise, Berkua, Effie, Nyx, Peri, Charlotte, Selena.
Kaze is your a ninja you will start with. He can marry Corrin, Felicia, Mozu, Hinoka, Sakura, Hana, Orochi, Rinkah, Kagero, Oboro, Setsuna, Camilla, Elise, Berkua, Azura, Effie, Nyx, Peri, Charlotte, Selena.
Fire Emblem Fates Birthright Marriages
Ryoma doesn’t join your party until a little later in the game. He can marry Felicia, Corrin, Mozu, Orochi, Azura, Rinkah, Kagero, Oboro, Setsuna, Camilla, Hana, Elise.
Takumi is an archer you will get after a few missions. He can marry Felicia, Hana, Azura, Mozu,Orochi, Rinkah, Corrin, Kagero, Oboro, Setsuna, Camilla, Elise.
Saizo is another ninja you will have on your team. He can marry Azura, Oboro, Felicia, Rinkah, Mozu, Hinkoka, Sakura, Corrin, Hana, Orochi, Kagero, Setsuna, Beruka, Charlotte.
Kaden is a beastkin that will join you as your progress through the story. He can marry Rinkah, Azura, Corrin, Felicia, Mozu, Hinkoka, Oboro, Sakura, Orochi, Hana, Kagero, Setsuna, Peri, Charlotte.
Hinata is a Samurai that you will get in after a few story missions. He can marry Azura, Felicia, Corrin, Mozu, Hinkoka, Orochi, Sakura, Kagero, Oboro, Setsuna, Hana, Rinkah, Peri, Selena.
Azama is a monk that you will get in after a few story missions. He can marry Azura, Felicia, Mozu, Hinkoka, Hana, Orochi, Corrin, Kagero, Oboro, Sakura, Setsuna, Rinkah, Effie, Beruka.
Subaki is a Sky Knight that you pretty early in the game. He can marry Azura, Oboro, Felicia, Mozu, Hinkoka, Orochi, Rinkah, Hana, Kagero, Sakura, Setsuna, Corrin, Selena, Nyx.
Hayato is a Diviner that you pretty early in the game. He can marry Azura, Oboro, Felicia, Mozu, Hinkoka, Sakura, Hana, Corrin, Orochi, Rinkah, Kagero, Setsuna, Effie, Nyx.
Fire Emblem Fates Conquest Marriages
Zander is one of your brothers and he will join you after a few story missions. He can marry Azura, Felicia, Mozu, Selena, Effie, Peri, Charlotte, Nyx, Beruka, Hinoka, Sakura, Corrin.
Leo is another one of your brothers and he will join you after a few story missions. He can marry Azura, Felicia, Mozu, Selena, Effie, Peri, Charlotte, Nyx, Beruka, Corrin, Hinoka, Sakura.
Benny is a knight that you get after a few story missions. few story missions. He can marry Azura, Felicia, Mozu, Selena, Effie, Nyx, Corrin, Peri, Charlotte, Beruka, Elise, Camilla, Oboro, Rinkah.
Keaton is a Wolfkin that you unlock after some story missions. few story missions. He can marry Felicia, Azura, Mozu, Selena, Effie, Corrin, Peri, Nyx, Charlotte, Beruka, Elise, Camilla, Hana, Rinkah.
Arthur is a fighter that you start with. He can marry Corrin, Azura, Felicia, Mozu, Selena, Effie, Peri, Nyx, Charlotte, Beruka, Elise, Camilla, Setsuna, Kagero.
Odin is a mage you will get pretty early in the game. He can marry Corrin, Felicia, Azura, Mozu, Selena, Effie, Nyx, Peri, Charlotte, Beruka, Elise, Camilla, Orochi, Kagero.
Laslow is a mercenary you will get pretty early in the game. He can marry Felicia, Corrin, Mozu, Selena, Azura, Effie, Peri, Nyx, Charlotte, Beruka, Elise, Camilla, Orochi, Hana.
Niles will come when Odin does pretty early in the game. He can marry Azura, Corrin, Felicia, Mozu, Selena, Effie, Peri, Nyx, Charlotte, Beruka, Elise, Camilla, Oboro, Setsuna.