4. Kitty & Colossus
Along with Cyclops & Jean and Rogue & Gambit, Kitty & Colossus have had one of the longest and most significant X-Men romances. The Days of Future Past story happened very shortly after a very young Kitty joined the team. There were hints to Kitty having a crush on Colossus prior to Days of Future Past, but nothing more had yet developed. In the Days of Future Past timeline Kitty and Colossus are married. They even had children that were killed by the Sentinels. The relationship between Kitty and Colossus did develop further in the normal X-Men timeline, after Kitty had grown up a bit. In X-Men: The Last Stand, we finally got Kitty and Colossus together in the main X-Men team. Unfortunately there was no hint of a romance between Kitty and Colossus, with Kitty used as a rival to Rogue for Iceman, and Colossus didnt even get any lines. The Days of Future past film is the perfect opportunity to delve into the romance of Kitty and Colossus.