4) The Last Night On Darillium
The Twelfth Doctor is the least romantic Doctor for a long while, but he still shared this one bittersweet moment with River Song, otherwise known as his wife.
The tragedy of the Doctor and River’s relationship is that, as time travellers, they always meet in the wrong order and at some point the Doctor knew he was going to meet River for one last time at the Singing Towers of Darilium (shortly before she dies, as seen in David Tennant’s “Silence In The Library.”)
In 2015 Christmas special “The Husbands of River Song,” we finally see this moment play out. In typical grouchy Capaldi fashion, the Doctor talks about “happily ever after” being an illusion – before revealing that the two of them have a whole 24 years left to spend together.